WO2015117106A1 - Polymer-grafted lignin surfactants - Google Patents

Abstract

A method of plasticizing cement includes including a polymer-grafted lignin in a mixture of cement and water. The polymer-grafted lignin is formed by grafting at least a first polymer with lignin. The at least a first polymer is formed via a controlled radical polymerization. The at least a first polymer is selected so that the polymer-grafted lignin is soluble in an aqueous fluid

Description

POLYMER-GRAFTED LIGNIN SURFACTANTS

CROSS-REFERENCE TO RELATED APPLICATIONS

[01] This application claims benefit of U.S. Provisional Patent Application Serial No. 61/965,597, filed February 3, 2014, U.S. Provisional Patent Application Serial No. 61/967,303, filed March 14, 2014, U.S. Provisional Patent Application Serial No. 61/996,670, filed May 14, 2014 and U.S. Provisional Patent Application Serial No. 62/071, 132, filed September 15, 2014, the disclosures of which are incorporated herein by reference.

BACKGROUND

[02] The following information is provided to assist the reader in understanding technologies disclosed below and the environment in which such technologies may typically be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document. References set forth herein may facilitate understanding of the technologies or the background thereof. The disclosure of all references cited herein are incorporated by reference.

[03] Biobased surfactants include anionic species based on hydrolyzed oils, cationic species based on the amino acid arginine, and nonionic species based on alkyl polyglycosides. These offer high levels of interfacial activity with lower environmental impact and have been studied extensively and used broadly in a range of applications. These biobased surfactants resemble purely synthetic surfactants with polar head groups and non- polar alkyl tails. Surfactants based on lignin have also been used in a broad range of applications, with lignosulfonates being the most broadly studied and used.

[04] Lignosulfonates are an anionic derivative of lignin, an abundant biopolymer that is the main byproduct of pulp and paper production as well as cellulosic ethanol production. Lignin is composed of three aromatic alcohols, which are polymerized to form a complex three-dimensional polymer. The size and chemistry depend on the source and how it was processed, but the native functional groups in lignin are aromatic, ether, and hydroxyl, which is present in primary, secondary, and phenolic forms. In neutral form, most types of lignin are soluble in dimethyl formamide and pyridine, and the solubility parameter is estimated to be 20-24 MPa^1/2. However, the phenolic groups are readily deprotonated, and lignins are soluble in basic aqueous solutions.

[05] Lignosulfonates, prepared through sulfite treatment of lignins, have been used as stabilizers in oil/water emulsions, surfactants in enhanced oil recovery, and plasticizers in concrete where they have provided only modest results. The anionic sulfonate group increases the hydrophilicity of lignin much like the phenoxide groups under basic conditions. Although a number of chemical strategies have been used to strengthen the amphiphilic interactions of lignin and lignosulfonate, such strategies have met with only limited success.

[06] Lignin is an abundant natural phenolic polymer that is a key structural component of woody plants and a waste material in a number or processes. Lignin is, therefore a potential sustainable building block of industrial materials. A goal for the effective handling of lignin waste involves the formation of lignin-based materials. For decades, these materials have been a source of interest because lignin is a natural, renewable source of carbon. Engineering uses for waste materials into high-performance materials would positively affect the environmental cost of producing these materials.

SUMMARY

[07] In one aspect, a method of plasticizing cement includes adding or including a polymer-grafted lignin in mixture of cement and water. The polymer-grafted lignin is formed by grafting at least a first polymer with lignin. The at least a first polymer is formed via a controlled radical polymerization. The at least a first polymer is selected so that the polymer- grafted lignin is soluble in an aqueous fluid. The first polymer may, for example, be a hydrophilic polymer. In a number of embodiments, the at least a first polymer has a degree of polymerization in the range of 10 to 1000. The average graft density of the at least a first polymer on the lignin (per unit surface area of the lignin particle as determined from an average particle size and assuming a spherical shape) may, for example, be in the range of approximately 0.000159 to 0.1592 grafts per nm², in the range of approximately 0.000159 to 0.0796 grafts per nm², in the range of approximately 0.000159 to 0.0398 grafts per nm², in the range of approximately 0.000159 to 0.0199 grafts per nm², or in the range of approximately 0.000159 to 0.00796 grafts per nm². In a number of other embodiment, the average graft density per unit surface area is in the range of approximately 0.000796 to 0.00796 grafts per nm² or in the range of approximately 0.001592 to 0.00557 grafts per nm². The at least a first polymer may be grafted from the lignin or grafted to the lignin. In a number of embodiments, the lignin includes a lignosulfonate, a kraft lignin, or other byproducts from the processing of biomass, such as trees or other plants.

[08] The at least a first polymer may, for example, be a poly(acrylamide), a poly(acrylic acid), a 2-acrylamido-2-methyl-N-propane sulfonate polymer or an oligoethylene oxide methacrylate polymer. In a number of embodiment, the at least a first polymer is formed from a monomer selected from the group consisting of, an acrylic acid monomer, an acrylamide monomer, or an acrylate monomer. The at least a first polymer may, for example, be formed from a monomer selected from the groups consisting of an acrylic acid monomer, a methacrylic acid monomer, an acrylamide monomer, a methacrylamide monomer, an acrylate monomer or a methacrylate monomer. The at least a first polymer may, for example, be formed from a monomer selected from the groups consisting of acrylic acid, acrylamide, hydroxyethyl acrylate, oilgoethylene acrylate, butyl trimethyl ammonium chloride acrylate, butyl trimethyl ammonium bromide acrylate, hydroxyethyl methacrylate, butyl trimethyl ammonium chloride methacrylate, and butyl trimethyl ammonium bromide methacrylate.

[09] In a number of embodiments, the polymer grafted lignin is included in the mixture of cement and water in the range of approximately 0.001 to 10 wt%, in the range of approximately 0.025 to 10 wt%, in the range of approximately 0.025 to 2 wt%. In a number of embodiments, the polymer grafted lignin is included in the mixture of cement and water in a concentration less than 2 wt%.

[10] The polymer-grafted lignins hereof may, for example, be included in a cementitious mixture as the sole plasticizer/superplasticizers. Other plasticizers/superplasticizers and/or other additives may also be present. In a number of embodiments, ungrafted lignin may be present in the mixture.

[11] In another aspect, a cementitious composition includes a polymer-grafted lignin, cement and water. As described above, the polymer-grafted lignin is formed by grafting at least a first polymer with lignin. The at least a first polymer is formed via a controlled radical polymerization. The at least a first polymer is selected so that the polymer-grafted lignin is soluble in an aqueous fluid.

[12] In a further aspect, a composition includes at least one liquid phase, and a surfactant suitable to lower a surface tension at a liquid-liquid or a liquid-gas phase boundary. The surfactant is formed by grafting at least a first polymer with lignin. The at least a first polymer is formed via a controlled radical polymerization. The at least a first polymer is selected so that the surfactant is soluble in the at least one liquid phase. The surfactant may, for example, be an emulsifier in the composition or a foaming agent in the composition. The at least a first polymer may, for example, be a hydrophilic polymer or a hydrophobic polymer. In a number of embodiments, the lignin includes a lignosulfonate, a kraft lignin, or other byproducts from the processing of biomass, such as trees or other plants..

[13] In a number of embodiments, the at least a first polymer has a degree of polymerization in the range of 10 to 1000. The average graft density of the at least a first polymer on the lignin (per unit surface area of the lignin particle) may, for example, be in the range of approximately 0.000159 to 0.1592 grafts per nm², in the range of approximately 0.000159 to 0.0796 grafts per nm², in the range of approximately 0.000159 to 0.0398 grafts per nm², in the range of approximately 0.000159 to 0.0199 grafts per nm², or in the range of approximately 0.000159 to 0.00796 grafts per nm². In a number of other embodiments, the average graft density per unit surface area is in the range of approximately 0.000796 to 0.00796 grafts per nm² or in the range of approximately 0.001592 to 0.00557 grafts per nm².

[14] The at least a first polymer may, for example, be a poly(acrylamide), a poly(acrylic acid), a 2-acrylamido-2-methyl-N-propane sulfonate polymer or an oligoethylene oxide methacrylate polymer . In a number of embodiment, the at least a first polymer is formed from a monomer selected from the group consisting of, an acrylic acid monomer, an acrylamide monomer, or an acrylate monomer. The at least a first polymer may, for example, be formed from a monomer selected from the groups consisting of an acrylic acid monomer, a methacrylic acid monomer, an acrylamide monomer, a methacrylamide monomer, an acrylate monomer or a methacrylate monomer. The at least a first polymer may, for example, be formed from a monomer selected from the groups consisting of acrylic acid, acrylamide, hydroxyethyl acrylate, oilgoethylene acrylate, butyl trimethyl ammonium chloride acrylate, butyl trimethyl ammonium bromide acrylate, hydroxyethyl methacrylate, butyl trimethyl ammonium chloride methacrylate, and butyl trimethyl ammonium bromide methacrylate.

[15] In a number of embodiments, the polymer grafted lignin is included in the mixture of cement and water in the range of approximately 0.001 to 10 wt%, in the range of approximately 0.025 to 10 wt%, in the range of approximately 0.025 to 2 wt%. In a number of embodiments, the polymer grafted lignin is included in the mixture of cement and water in a concentration less than 2 wt%.

[16] In a number of embodiments, the at least one liquid phase is an aqueous emulsion phase, and the composition further includes at least a second liquid phase which is an oleophilic phase. In a number of embodiments, the at least one liquid phase is an oleophilic emulsion phase, and the composition further includes at least a second liquid phase which is an aqueous phase. In a number of embodiments, the surfactant is adapted to stabilize an aqueous/oleophilic emulsion.

[17] The polymer-grafted lignins hereof may, for example, be included in a composition hereof as the sole surfactant. Other surfactants and/or other additives may also be present. In a number of embodiments, ungrafted lignin may be present in the composition.

[18] In still a further aspect, a method of lowering a surface tension at a liquid-liquid or a liquid-gas phase boundary a composition including at least a first liquid phase includes adding a surfactant adapted to lower the surface tension. The surfactant is formed by grafting at least a first polymer with lignin. The at least a first polymer is formed via a controlled radical polymerization. The at least a first polymer is selected so that the surfactant is soluble in the first liquid phase. As described above, the surfactant may, for example, be an emulsifier in the composition or a foaming agent in the composition. The at least a first polymer may, for example, be a hydrophilic polymer or a hydrophobic polymer.

[19] The present systems, methods and compositions, along with the attributes and attendant advantages thereof, will best be appreciated and understood in view of the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[20] Figure 1A illustrates an embodiment of a synthetic strategy for preparing a lignin RAFT macroinitiator.

[21] Figure IB illustrates a representative embodiment of the preparation of a polymer- grafted lignin using reversible addition-fragmentation chain transfer (RAFT). [22] Figure 1C illustrates a representative embodiment of synthesis of a lignin grafted with glycidyl methacrylate (GM).

[23] Figure ID illustrates a representative embodiment of synthesis of lignin grafted with poly(acrylamide) (PAm) via free radical polymerization (FRP).

[24] Figure 2 illustrates a comparison of surface tension values as a function of concentration of aqueous solutions of lignin grafted with poly(acrylic acid) PAA, lignin grafted with PAm, and acidified lignin, which was used in the preparation of the polymer- grafted lignins.

[25] Figure 3A illustrates a photograph of a hexane/water emulsion formed with PAm- grafted lignin.

[26] Figure 3B illustrates a photograph of a hexane/water emulsion formed with PAA- grafted lignin.

[27] Figure 4A illustrates the volume fraction of an emulsion and the fraction of lignin in the emulsion phase for a hexane/water emulsion formed with PAm-grafted lignin.

[28] Figure 4B illustrates the volume fraction of an emulsion and the fraction of lignin in the emulsion phase for a hexane/water emulsion formed with PAA-grafted lignin.

[29] Figures 4C illustrates an idealized potential conformation of polymer-grafted lignin at an air-water interface.

[30] Figure 4D illustrates an idealized potential conformation of polymer-grafted lignin at a water-hexane interface.

[31] Figure 5 illustrates foam stability studies of lignin grafted with PAm and PAA at grafting densities of 100

lignin) and graft degree of polymerization (DP) of 50 and 100 compared to a standard foaming agent (ethoxylated and sulfated alcohol (AES)).

[32] Figure 6A illustrates size characterization of PAm-grafted lignin formed via RAFT, pAm-grafted lignin formed via FRP and polycarboxylate ether (PCE) measured using dynamic light scattering (DLS) [33] Figure 6B illustrates a proposed structure of PAm-grafted lignin synthesized via RAFT.

[34] Figure 6C illustrates a proposed structure of PAm-grafted lignin synthesized via FRP.

[35] Figure 7A illustrates an enlarged view of the scale used for slump tests with a RAFT-lignin-PAm sample.

[36] Figure 7B illustrates a slump test at 0.42 water/cement (w/c) ratio showing the diameter and height for Portland cement.

[37] Figures 7C illustrates a slump test at 0.42 w/c ratio showing the diameter and height for PCE (0.05 wt%).

[38] Figures 7D illustrates a slump test at 0.42 w/c ratio showing the diameter and height for RAFT-lignin-PAm (0.05 wt%).

[39] Figure 8A illustrates slump spread as a function of superplasticizer concentration for Portland cement, PCE, RAFT-lignin-PAm, and FRP-lignin-PAA.

[40] Figure 8B illustrates slump spread as a function water content at a superplasticizer concentration of 0.05 wt% for Portland cement, PCE, and RAFT-lignin-PAm.

[41] Figure 8C illustrates slump spread as a function water content at a superplasticizer concentration of 0.1 wt% for Portland cement, PCE, and RAFT-lignin-PAm.

[42] Figure 9A illustrates viscosity as a function of oscillation strain for Portland cement, PCE, RAFT-lignin-PAm, and FRP-lignin-PAA cement pastes (w/c = 0.42) at a superplasticizer concentrations of 0.05 wt.%.

[43] Figure 9B illustrates viscosity as a function of oscillation strain for Portland cement, PCE, RAFT-lignin-PAm, and FRP-lignin-PAA cement pastes (w/c = 0.42) at a superplasticizer concentrations of 0.1 wt.%.

[44] Figure 10 illustrates adsorption data for the studied materials of Figures 9A at different concentrations for cement phases normalized to the BET (Brunauer, Emmett and Teller) surface area of cement mineral (reported parenthetically in m²/g along with the zeta potential value) wherein (a) is dicalcium silicate (C2S) (BET = 0.9845 ± 0.0099 m²/g; ζ = - 5.96 ± 0.42 mV); (b) is tricalcium silicate (CsS) (BET = 0.8252 ± 0.0047 m²/g; ζ = -7.77 ± 0.32 mV); (c) is tricalcium aluminate (C3A) (BET = 0.3492 ± 0.0133 m²/g; ζ = +3.23 ± 0.44 mV); and (d) is tetra-calcium aluminoferrite (C₄AF) (BET = 0.5797 ± 0.0017 m²/g; ζ = +26.35 ± 1.46 mV).

[45] Figure 1 1 illustrates compressive strengths measured for samples at 7 days and 28 days for Portland cement, PCE/cement, RAFT-lignin-P Am/cement, and FRP-lignin- PAA/cement.

DETAILED DESCRIPTION

[46] It will be readily understood that the components of the embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations in addition to the described representative embodiments. Thus, the following more detailed description of the representative embodiments, as illustrated in the figures, is not intended to limit the scope of the embodiments, as claimed, but is merely illustrative of representative embodiments.

[47] Reference throughout this specification to "one embodiment" or "an embodiment" (or the like) means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" or the like in various places throughout this specification are not necessarily all referring to the same embodiment.

[48] Furthermore, described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the various embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, et cetera. In other instances, well known structures, materials, or operations are not shown or described in detail to avoid obfuscation.

[49] As used herein and in the appended claims, the singular forms "a," "an", and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a polymer" includes a plurality of such polymer and equivalents thereof known to those skilled in the art, and so forth, and reference to "the polymer" is a reference to one or more such polymers and equivalents thereof known to those skilled in the art, and so forth. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, and each separate value, as well as intermediate ranges, are incorporated into the specification as if individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contraindicated by the text.

[50] As user herein, the term "polymer" refers to a chemical compound that is made of a plurality of small molecules or monomers that are arranged in a repeating structure to form a larger molecule. Polymers may occur naturally or be formed synthetically. The use of the term "polymer" encompasses homopolymers as well as copolymers. The term "copolymer" is used herein to include any polymer having two or more different monomers. Copolymers may, for example, include alternating copolymers, periodic copolymers, statistical copolymers, random copolymers, block copolymers, graft copolymers etc. Examples of polymers include, for example, poly(acrylamide) and poly(acrylic acid), which are synthetic hydrophilic polymers.

[51] Lignin is a complex, cross-linked racemic macromolecule or biopolymer that is a key structural component of woody plants. Three monolignol monomers of lignin (which are methoxylated to various degrees), p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol, are incorporated into lignin in the form of the phenylpropanoids p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S), respectively. Different types of lignin are described depending on the composition of monolignols and means of isolation. Lignin may, for example, be obtained from kraft pulping, sulfite pulping, soda process, organic solvent processes, steam explosion processes, and dilute acid (for example, sulfuric acid) processes. In general, any type of lignin can be used in the compositions hereof, including, for example, kraft lignin, solvolysis lignin, organosolv lignin, steam exploded lignin, wood waste, natural wood, corn stalk, biopitch, molasses, wood meal and coffee grounds.

[52] In a number of embodiments, polymer-grafted lignin agents are used to modify or enhance the amphiphilic nature of lignin. The composition hereof include a lignin core with one or more polymer segment grafted thereon. [53] In the compositions hereof, the number of polymer grafts on a lignin core, as well as the molecular weight, polydispersity, and the type/nature of polymer(s) grafted to a lignin core can be adjusted/controlled to achieve a desired result which may, for example, dictated by the intended use. Likewise, the number of lignin cores to which a particular polymer chain is connected can be controlled to, for example, prevent crosslinking between multiple lignin cores. In that regard, in a number of embodiments hereof, each grafted polymer is attached only to a single lignin core. In a number of embodiments, each of the polymers grafted to lignin core is of the same type (that is, formed from the same monomer or monomers). Moreover, the molecular weight and polydispersity of the grafted polymer can be well controlled (for example, via controlled radical polymerization). Polydispersity can, for example, be maintained less than 2, less than 1.5 or less than 1.2. In a number of embodiments, different types of polymers, as well as polymer of differing molecular weight or broad or differing polydispersity, may be grafted to the same lignin core.

[54] A number of chemical methods are suitable for preparing polymer-grafted lignin agents or materials hereof. Polymers grafted to lignin may, for example, vary in structure: including, for example, linear polymers, branched polymers etc. Methods for creating polymer-grafted lignin materials include grafting-from approaches and grafting-onto approaches.

[55] In a number of representative examples of a grafting from approach, hydrophilic polymers were grafted from kraft lignin to form surfactants. As used herein, the term "surfactant" is used to refer to a composition including a lignin core and one or more polymer segments grafted thereon, which lower surface tension or interfacial tension in a liquid (for example, between two liquids or between a liquid and a solid). Surfactants may, for example, act as detergents, wetting agents, emulsifiers, dispersants or foaming agents. An emulsifier is a surfactant which stabilized an emulsion, which is a mixture of two or more liquid that are normally immiscible. A foaming agent facilitates the formation of a foam. A dispersant (including plasticizers and superplasticizers) is added to a suspension to improve separation of particles and prevent settling or climbing. In a number of embodiments, polymer-grafted lignins hereof are soluble in a liquid phase to function as an emulsifier or a foaming agent.

[56] In a number of embodiments, the lignin core has an average diameter on the order of approximately 5-500 nm and average grafting density may, for example, be varied between approximately 1-200, 1-100, 1-50, 1-25, 1-10 or 2-7 grafts/lignin particle. However, the graft density may, for example, depend in part of the size of the lignin particle and the number of sites for grafting, which may be varied using established chemical modification strategies. It may also be affected by the presence of non-grafted lignin. Normalize for surface area of lignin particles (as determined based upon and idealized spherical shape), average grafting density per unit surface area may, in a number of embodiments, be in the range of approximately 0.000159 to 0.1592 grafts per nm² as described above. The grafted materials may, for example, be prepared using a living or controlled radical polymerization (CRP) such as reversible addition-fragmentation chain transfer (RAFT) or atom transfer radical polymerization (ATRP). The use of CRP in grafting polymers with lignin (in either a grafting from or grafting two approach) to form dispersants, particularly in polymeric matrices, is disclosed in PCT International Patent Application Publication No. WO/2014/116672.

[57] CRP enable the control of polymer compositions, architectures, and functionalities for the development of materials with a specific set of properties. ATRP, RAFT, nitroxide mediated polymerization (NMP), and catalytic chain transfer (CCT), ring-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) are representative examples of controlled/living radical polymerization processes or CRP that provide versatile methods for the synthesis of polymers from a broad spectrum of monomers with controlled molecular weight, low polydispersity and site specific functionality. CRP processes provide compositionally homogeneous, well-defined polymers (with predictable molecular weight, narrow molecular weight distribution, and, potentially, chain end- functionalization). CRP have been the subject of much study as reported in several review articles. See, for example, Matyjaszewski, K., Ed. Controlled Radical Polymerization; ACS: Washington, D. C, 1998; ACS Symposium Series 685. Matyjaszewski, K., Ed. Controlled/Living Radical Polymerization. Progress in ATRP, NMP, and RAFT; ACS: Washington, D. C, 2000; ACS Symposium Series 768. Matyjaszewski, K., Davis, T. P., Eds. Handbook of Radical Polymerization; Wiley: Hoboken, 2002. Qiu, J.; Charleux, B.; Matyjaszewski, K. Prog. Polym. Sci. 2001, 26, 2083. Davis, K. A.; Matyjaszewski, K. Adv. Polym. Sci. 2002, 159, 1.

[58] ATRP is presently one of the most robust CRP and a large number of monomers can be polymerized providing compositionally homogeneous well-defined polymers having predictable molecular weights, narrow polydispersity, and high degree of end- functionalization. Matyjaszewski and coworkers disclosed ATRP, and a number of improvements in the basic ATRP process, in a number of patents and patent applications. See, for example, U.S. Patent Nos. 5,763,546; 5,807,937; 5,789,487; 5,945,491 ; 6, 1 11,022; 6,121,371; 6, 124,41 1; 6, 162,882; 6,624,262; 6,407,187; 6,512,060; 6,627,314; 6,790,919; 7,019,082 ; 7,049,373; 7,064, 166; 7, 157,530, U.S. Patent Application Ser. Nos. 09/534,827; and PCT International Patent Application Nos. PCT/US04/09905; PCT/US05/007264; PCT/US05/007265; PCT/US06/33152 and PCT/US2006/048656, the disclosures of which are herein incorporated by reference.

[59] RAFT polymerization has similarities to ATRP with a chain-transfer agent (CTA) controlling the instantaneous concentration of propagating radicals. In a number of representative examples, one may graft a macroinitiator onto the lignin particle surface and perform RAFT polymerization.

[60] One or more polymer segments or chains may, for example, be grafted from the lignin of the agent or grafted to the lignin of the agent.

[61] As described above, grafting-from lignin methods may also include nitroxide- mediated polymerization (NMP). NMP is a method of radical polymerization using an alkoxyamine initiator to generate polymers with controlled stereochemistry and low polydispersity. NMP is a type of reversible-deactivation radical polymerization. The persistent radical is the nitroxide species in NMP.

[62] Surface-initiated ring opening polymerization (ROP) of cyclic monomers, such as lactide and caprolactone, may, for example, be carried out using a stannous octanoate catalyst.

[63] Ring-opening metathesis polymerization (ROMP) may also be used to catalyze polymerization to achieve polymer-grafting from lignin. In this approach, a ruthenium catalyst is covalently attached to the surface, and polymerization of strained monomers, such as nornbornene, proceeds and can include a range of substituents.

[64] As described above, a grafting-onto or grafting-to procedure can also be used to form polymer-grafted lignin. CRP may, for example, be used to prepare the polymers for grafting onto a lignin core. As described above, CRP provide methods of forming polymers with a high degree of (and varying) end functionalization. A polymer may, for example, be synthesized from one or more monomers using a CRP such as ATRP with a copper catalyst. In a number of embodiments, the initiator is ethyl-2-bromoisobutyrate (EBiB), which leaves a terminal bromine on the polymer. Lignin may be deprotonated in aqueous solution leaving the phenoxide group. When stirred together in solution, the phenoxide displaces the terminal bromine (or another electrophilic functional group) to provide the final lignin-based material. The NMR produced from the solids obtained after the reaction of the lignin phenoxide salt with the polymer. Additionally, elevated temperature or other optimization of reaction conditions may facilitate polymer-lignin coupling.

[65] In another example of a grafting onto approach, conjugation occurs via, for example, Grignard-modified polystyrene, in a suitable solvent or in the melt state. The polymer may, for example, again be synthesized via ATRP using a copper catalyst with ethyl 2-bromoisobutyrate (EBiB) as the initiator, leaving the terminal bromine. Lignin is oxidized after reacting with sodium periodate, forming an ort/zo-quinone functionality. Bromine- terminated polymer may be reacted with a turbo Grignard to produce a Grignard reagent. The desired lignin-based material may be synthesized by reacting the Grignard-modified polymer with the oxidized lignin. The product species may, for example, be formed by attack of the Grignard on one of the susceptible carbonyl carbons.

[66] In another example of a grafting onto approach, a click coupling (for example, via copper-catalyzed Huisgen cycloaddition of an alkyne and azide), is used to form polymer- grafted lignin. One approach is to functionalize lignin with an alkyne and the polymer terminus with an azide. ATRP may, for example, be used to prepare a polymer with a terminal bromine that can be substituted by reaction with sodium azide, and lignin can be functionalized with an alkyne by reacting with 4-pentynoic acid using of N,N- dicychlohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) in DMF to form an ester linkage.

[67] Other polymer chemistries may be used to produce polymers amenable to grafting onto methodologies. A representative example is Grignard metathesis (GRIM) polymerization. GRIM polymerization may, for example, be used to prepare poly(3-hexyl thiophene) with terminal amines that can be used to form amide bonds with lignin carboxylic acid groups, or with pendant azide groups that can be used to couple to alkyne-functionalized lignin via click reactions. [68] Ring opening metathesis polymerization may also be used to prepare polymers with reactive groups. Tert-butyl ester norbornene imide (tBENI) and N-methyloxanorbornene imide (NMONI) capped by cz^'s-olefin termination agents with reactive functional groups, such as acetate and a-bromoesters (7), may, for example, be polymerized. Those and other functionalization groups may, for example, be used to make polymers capable of grafting onto lignin.

[69] Using CRP synthetic techniques as, for example, describe above, polymers that are hydrophilic or hydrophobic may, for example, be grafted from or to lignin to solubilize the resultant polymer-grafted lignin in aqueous or non-aqueous (or oleophilic/hydrophobic) fluids.

[70] Surfactants

[71] In a number of embodiments, compositions hereof include a lignin core with grafted polymer(s) (for example, synthetic polymers) that result in materials with improved properties, tunable for solubility. For example, kraft lignin grafted with hydrophilic polymers was prepared using reversible addition-fragmentation chain-transfer polymerization (RAFT) and investigated for use as, for example, an emulsifier and/or a foaming agent. In a number of representative studies, polyacrylamide and poly(acrylic acid) were grafted from a lignin macroinitiator at average graft densities of approximately 2 per particle (grafting density of 100

lignin)) and 15 per particle (grafting density of 670 lignin)) and with target degrees of polymerization of 50 and 100. Dynamic light scattering data indicated polymer-grafted lignin aggregated in aqueous media, with sizes up to 100 nm. The compositions were surface active, reducing the surface tension to as low as 42 dynes/cm, an effect that could be tuned or controlled on the basis of, for example, polymer chemistry and graft density. While the polymer-grafted lignin was soluble in water at concentrations of 1 mg/mL, it was not soluble in a hydrocarbon such as hexane. Unexpectedly, the polymer- grafted lignin was used to form water-in-oil emulsions formed from equal volumes of water and hexanes, with average droplet sizes that were less than 100 μιη. While polymer-grafted lignin has structural features similar to particles used in Pickering emulsions, its interfacial behavior is qualitatively different. Without limitation to any mechanism, studies hereof suggest the lignin core may be influencing the interfacial activities. Lignosulfonates have established use as dispersants and emulsifiers but generally are not effective foaming agents. Grafting of hydrophilic monomers to kraft lignin via controlled radical polymerization will augment its use in a broad range of applications. Additionally, polymer-grafted lignin materials hereof have utility as a new type of superplasticizer that, for example, provides substantial improvement in stabilizing and reducing yield stress and/or viscosity in aqueous cement suspension. The grafted architecture of the polymer-grafted lignins hereof may, for example, promote stronger lignin-particle interactions and more effective inhibition of aggregation by the polymer corona.

[72] Several representative examples of the synthesis and characterization of the properties of kraft lignin grafted with polymers, created using reversible addition- fragmentation chain-transfer (RAFT) polymerization from a lignin macroinitiator are described herein.

[73] An embodiment of a synthetic strategy for preparing a lignin RAFT macroinitiator is shown in Scheme 1 of Figure 1A. A representative embodiment of the preparation of a polymer-grafted lignin using RAFT is shown in Scheme 2 of Figure IB.

[74] The macroinitiator of Figure 1A was characterized via ¾ NMR. Peaks associated with the ethyl group in the xanthate moiety were identified. The peak from the pentafluorobenzaldehyde (PFB) used for quantification of initiator density was also identified. All the representative compositions (summarized in Table 1) were soluble in water at 1 mg/mL. Stable emulsions were formed when mixed with hexanes in an ultrasonicator. Quantitative data showed that the poly(acrylic acid) partitions more strongly into the emulsion phase.

Table 1:

[75] Analysis of PAm cleaved from Lignin676PAml00 under basic conditions was performed by ¾ NMR and gel permeation chromatography (GPC). A colorless solution was extracted from the dried product, and ^XH NMR data confirmed it was PAm with no signs of lignin aromatic peaks. GPC data suggested the molecular weight of the cleaved polymer was higher than expected based on the molar ratio of initiator sites: acrylamide with M_n of 1 1,300 g/mol, corresponding to a degree of polymerization of 159 instead of the expected 100, and polydispersity of 1.83.

[76] As discussed above, all polymer-grafted lignin compositions were soluble in water at 1 mg/mL. Dynamic light scattering was used to measure particle size. The DLS data had two main peaks for all compositions. Particle size is summarized in Table 2. The aggregation of polymer-grafted lignin appeared to be a stronger function of degree of polymerization than of graft density. Furthermore, these data also suggest that little or no homopolymerization of PAA or PAm occurred under these conditions, and that the grafted product was the major one.

[77] Without limitation to any mechanism, the driving force for aggregation was assumed to be water-lignin interactions, which likely promoted a collapsed lignin conformation at pH 7. This suggests that surfactants based on lignin grafted with hydrophilic polymers may be considered as a polymer-grafted nanoparticle, similar to those investigated extensively in Pickering emulsions.

Table 2

[78] The surface tension values of aqueous solutions of lignin grafted with PAA and PAm as a function of concentration are shown in Figure 2 and compared with acidified lignin used in the preparation of the polymer conjugates. Non-grafted lignin had only weak effects on the surface tension, with an inflection point appearing near 1 mg/mL (the concentration at which particle aggregates become visible in solution). In contrast, a sharp decrease in surface tension at concentrations slightly less than 0.1 mg/mL was observed for both polymer-grafted compositions, consistent with a critical micelle concentration or critical aggregation concentration (CAC). The studied PAA compositions tended to lower the water surface tension to a greater extent than those based on PAm, and this effect was found to be dependent on grafting density and degree of polymerization. The CAC appeared to be independent of those variables, indicating the CAC may be associated with the transition to larger (but still nanoscale) aggregates.

[79] The samples with grafted PAm generally had more modest changes in surface tension relative to that of water (72.8 dynes/cm) than the ones with PAA, which had a low value of 42 dynes/cm for the higher grafting density and lower graft molecular weight. This value is significantly lower than the surface tension observed for aqueous solutions of PAA (73 dynes/cm) and PAm (69 dynes/cm) polymer, providing further confirmation of the effectiveness of the grafted architecture.

[80] Sodium lignosulfonate can reduce the air/water surface to 50 dynes/cm at concentrations of 1 mg/mL, a concentration which is higher than traditional surfactants and attributed to the disorganized structure of hydrophilic and lipophilic moieties in lignosulfonates. PEGylated kraft lignin (64.8% ethylene oxide by mass) can reduce the air/water surface tension to 44 dynes/cm at a CAC of 0.25 mg/mL. Such results suggest that the chemistry of the hydrophilic groups will affect the surface energies of corresponding solutions.

[81] While the concentration dependence in Figure 2 is summarized as CAC values, the experiments measured partitioning of different lignin species to the air-water interface and their effects on surface tension. In comparison, nonionic surfactants, such as polyoxoethylene-alkanols, can reduce the surface tension to 35 mN/m at critical micelle concentrations of order 10^~4 M (ca. 0.04 mg/mL for hexaoxyethylene w-dodecanol, C12E6). While the surfactants such as polyoxoethylene-alkanols reduce the surface tension by presenting alkyl groups normal to the water surface and thereby reducing the cohesive energy of the interface and the resultant surface tension, it is not yet clear what drives the polymer- grafted lignin to saturate the air-water interface at lower concentrations than non-grafted lignin. Without limitation to any mechanism, we hypothesized that in a system with a CAC, partitioning to the surface competes with the formation of aggregates in bulk solution, and surface partitioning competes more effectively when hydrophilic polymers inhibit lignin- lignin interactions that drive aggregation. This suggests that the air-water interface is enriched in lignin with hydrophilic polymer grafts preferentially extending into the bulk water.

[82] Viscosities at concentrations of 10 and 50 mg/mL were measured using a cone- and-plate rheometer. These values did not differ significantly from those of water and suggested the polymer grafts did not entangle appreciable at these concentrations. Surface tension and viscosity values are summarized in Table 3.

Table 3

[83] To test emulsion formation, all grafting compositions were dissolved in water at 1 mg/mL and pH 7, then emulsions were formed by adding an equal volume of hexanes followed by ultrasonication. Photomicrographs of representative solutions are shown in Figure 3A and 3B. Generally two phases were observed in which emulsions were in equilibrium with an aqueous phase, but the hexanes phase appeared to be completely incorporated into the emulsion regardless of polymer graft chemistry, density, or degree of polymerization at the surfactant concentrations studied. In contrast, non-grafted lignin in water at 1 mg/mL showed a lower tendency to stabilize emulsions based on mixing with equal volume of hexanes. In these samples, three phases were observed and the volume fractions of hexanes:emulsion:water were 40%:20%:40%. It may be concluded that the tendency to form stable emulsions is linked to polymer grafting.

[84] Droplet sizes of 5-40 μιη were observed in the emulsion phases, as shown in Figure 3A and 3B. The droplets in the PAA-grafted lignin emulsions (see Figure 3B) were found to be smaller than those in emulsions formed using PAm-grafted lignin (see Figure 3B), with average droplet sizes of 10 μιη and 20 μιη, respectively. These emulsions were stable for weeks at room temperature.

[85] The continuous phase in the emulsions for all lignin surfactant compositions was identified as hexane using conductivity measurements. This was unexpected because polymer-grafted lignin is insoluble in hexanes and Pickering emulsions are modeled as reducing the interfacial energy according to:

where r is the particle radius, γοπ is the interfacial tension, and 9ow is the contact angle. Since Qow < 90° for a particle that is soluble in water, this would predict water would form the continuous phase in these emulsions, which forms the basis for the Bancroft Rule (which states that the phase in which an emulsifier is more soluble constitutes the continuous phase). Without limitation to any mechanism, that the continuous phase was found to be hexanes suggests that lignin grafted with hydrophilic polymers may be amphiphilic, potentially behaving as patchy particles with the polymer grafts acting as hydrophilic domains and the exposed lignin core acting as a particle core with mixed hydrophilic and hydrophobic interactions.

[86] To understand better the formation of water- in-oil (or aqueous/oleophilic) emulsions, Lignin676Am50 and Lignin676AA50 were tested at pH 7 in water at a concentration of 1 mg/mL in a series ranging from 10% to 90% water. The volume fraction of emulsion was determined by measuring the relative heights of the phases, and the fraction of lignin in the emulsion phase was determined by measuring the residual concentration of lignin in the aqueous phase using UV-vis spectroscopy at an absorption wavelength of 290 nm, which has been used to quantify kraft lignin concentration in solution. The results are set forth graphically in Figure 4A (Lignin676Am50) and 4B (Lignin676AA50).

[87] At all compositions tested, hexanes were found to be the continuous phase, with no emulsion inversion point (EIP) identified. The fraction of the emulsion phase decreases almost linearly as the water fraction increases, suggesting that, for a given lignin surfactant, the emulsion has an essentially constant structure in terms of water droplet size and volume fraction.

[88] The PAA-grafted lignin was found to partition into the emulsion phase much more strongly, with greater than 65% in the emulsion at all water-hexanes mixtures tested compared to less than 35% of the PAm-grafted lignin. Those results were consistent with the observation that average droplet size was found to be smaller in the PAA-grafted lignin emulsions. All hexanes/water/polymer-grafted lignin samples prepared formed two-phase mixtures consisting of an emulsion phase and an aqueous phase.

[89] The difference in partitioning of lignin-g-PAA and lignin-g-PAm, shown in Figures 4A and 4B, correlated with the difference in droplet size observed in the emulsion phases, shown in Figures 3A and 3B. By mass balance, and without limitation to any mechanism, those results suggest that the molecular density of the two grafted lignins at the water-hexanes interface may be similar and that the difference in droplet size is driven by the lower surface tension of the PAA-grafted material.

[90] The stabilization of water-in-oil (W/O) emulsions or aqueous/oleophilic contrasts emulsions with that of lignosulfonates, which exclusively stabilize oil-in-water (O/W) or oleophilic/aqueous emulsions. Lignosulfonates do not form micelles effectively, but they do have hydrophilic and lipophilic moieties and behave as surfactants. Their disorganized structure is thought to reduce overall interfacial activity, requiring higher concentrations to achieve reductions in interfacial tensions than for traditional surfactants based on polar head groups and non-polar tails. The reductions in CAC and air/water surface tension observed with kraft lignin grafted with PAA and PAm indicated these hybrid biopolymers should be able to organize better at polar interfaces, providing high levels of surface activity. [91] Most polyoxoethylene-alkanol surfactants demonstrate an EIP, a water-oil composition around which water or oil continuous phases are observed as the oikwater volume ratio is varied. For example, a 1% poly oxy ethylene nonyl phenol (ΝΡΕΘ) solution mixed with paraffin oil has an EIP near 0.5 meaning that below water volume fractions of 50%, W/O emulsions are formed, while above this O/W emulsions are formed. Without limitation to any mechanism, the formation of W/O emulsions herein may be a result of relatively low grafting density and random placement of grafts on the lignin particles. If the polymer-grafted lignin were on the water side, the patchy structure with extended polymer grafts may lead to incomplete coverage and a high-energy interface. Segregation of lignin-g- PAA and lignin-g-PAm to the hexanes side of the interface may, for example, be a result of collapsed graft conformations (except for chains that may be extending directly into the water phase) that allow for higher coverage at the interface and better shielding of hexanes-water interactions. In contrast, lignosulfonates with compact hydrophilic sulfonate groups can pack more efficiently on the water side of the emulsion interface, leading exclusively to the formation of O/W emulsions. Potential conformations of polymer-grafted lignin are shown schematically in Figure 4C and 4D in which the polymer grafts are assumed to adopt extended conformations at the air-water interface but collapsed conformations at the hexanes- water interface.

[92] The architecture of polymer-grafted lignin may be altered to affect interfacial properties. For example, at the lower grafting density investigated in the current work, approximately 2 polymer chains per lignin particle, the lignin core is expected to be exposed to solvent, and the thermodynamics of that interaction would contribute to the contact angle made at the three-phase contact line. The nature of emulsions formed with the polymer- grafted lignins here may, for example, be adjustable via adjustment of graft density and/or other variables.

[93] Further evidence for the involvement of the lignin core in determining the interfacial activities comes from analyzing the dependence of the surface tension on composition. Studies of other types of polymer-grafted nanoparticles have shown surface tension may be a function of grafting density. While it is difficult to estimate the grafting density on the lignin particles, the estimates based on assuming a 5 nm particle size indicated a low or moderate grafting density. From this observation and the strong emulsification that was observed, it may be concluded that the lignin core contributes to the reductions in surface tension and is a contributor to the interfacial properties of these surfactants. Applications of these materials may, for example, leverage the native interfacial functions of lignin to act as a dispersant of solid particles in aqueous media.

[94] Grafting water-soluble polymers onto kraft lignin using RAFT has thus been used to prepare lignin-based surfactants using polyacrylamide or PAm and poly(acrylic acid) or PAA as representative hydrophilic polymers. While the solution viscosities did not increase significantly, surface tensions were found to decrease as a function of concentration, graft density, graft molecular weight, and polymer chemistry. Despite the aqueous solubility of the lignin conjugates, stable water-in-oil emulsions formed with hexanes, and the partitioning of the polymer-grafted lignin into the emulsion phase was found to be significantly greater for poly(acrylic acid) than polyacrylamide. For the compositions investigated, the surfactant properties of polymer-grafted lignin were shown to depend on both the polymer grafts as well the lignin core. The results of the studies hereof indicate that polymer-grafted lignin may be particularly useful in applications where the lignin core has strong affinity for other phases such as dispersants of polar solids.

[95] In further representative examples, polymer-grafted lignin was tested as a foaming agent in lab models of enhanced oil recovery when compared to a standard foaming agent such as an ethoxylated and sulfated alcohol (AES). The foams were tested on a Robinson cell, which is used to mimic the conditions of oil recovery and measures how the surfactant will perform. In a number of studies, 0.25 wt.% of surfactant was mixed in a 5 wt.% brine solution and then was mixed vigorously in a 1 : 1 volume ratio with CO2. The foams were tested at room temperature and a pressure of 2500 psi. The height of the foam was recorded over a course of four hours from the top of the cell and the bottom of the cell. The height of the foam decreases from the bottom of the cell whereas the top remains the same at 100 % throughout the experiment as the foam is generated on the bottom. Ideally the height of a good foaming agent will decrease very slowly, which translates into monotonic increase in the curves at -100% to 0% corresponding to foams in the brine phase. For these experiments the reference foaming agent stabilized at approximately -50% after approximately 150 minutes. Lignosulfonates have been previously used as foaming agents in the past decade. However, the foams formed using lignosulfonates cannot be sustained for more than half a minute. In comparison, to the lignosulfonates, polymer-grafted lignin formed a stable foam, equilibrating in 20 minutes to foam heights at -23% for the duration of the experiments. The experiments compared lignin grafted with polyacrylamide (PAm) and poly(acrylic acid) (PAA) at grafting densities of 100

lignin) and graft degree of polymerization (DP) of 50 and 100. For these compositions, the greatest foam stability was observed for formulations have DP of 100, independent of graft chemistry or grafting density (Figure 5). Those results suggest further increasing the DP may further enhance foam stability, and the application as of compositions hereof as foaming agent is apparent.

[96] Cement additive/Superplasticizer

[97] In general, a cement is a binder or a substance that sets and hardens. Cements, can for example, bind other materials together. Cement is generally a powdery substance made with calcined lime and clay. Cement may, for example, be mixed with water and aggregate, such as sand, to form mortar or mixed with sand, gravel, other aggregate components, and water to make concrete. Cement includes a variety of natural minerals that react with water to form high-strength solids. Mineral phases of cement are often based on calcium, silicon, and aluminum oxides and hydroxides, that often react with water (hydraulic cement) or carbon dioxide (non-hydraulic cement) to form solids. A number of cements may, for example, be prepared by calcining mineral precursors (for example, lime/limestone and clay) or from natural (pozzolan) sources, such as volcano ash. Some natural sources are referred to as geopolymers, which may, for example, be used directly or with thermal treatment. A number of cements are mixtures of common synthetic cement, such as Portland cement, mixed with other minerals, such as fly ash, silica, zeolites, clays, and limestone (often referred to as Supplementary Cementitious Materials or Alternative Supplementary Cementitious Materials). Non-hydraulic cement will not typically set in wet conditions or underwater. Non-hydraulic cement sets as it dries and reacts with carbon dioxide in the air. Hydraulic cement may, for example, be produced by replacing some of the cement in a mixture with, for example, activated aluminium silicates, pozzolanas, such as fly ash, etc. The chemical reaction results in hydrates that have limited water-solubility. Such hydrates that are durable in water and exhibit improved resistance to chemical attack. Hydraulic cement (for example, Portland cement) may also set in wet condition or underwater. Hydraulic cements can include aggregate, such as sand, gravel, or other solids, resulting in mortar or concrete.

[98] As described above, minerals in, for example, hydraulic cement undergo partial dissolution and remineralization, forming an intermediate phase often referred to as a microgel. This microgel is commonly referred to as cement paste. During this hydration process the mineral particles continue to react with other mineral particles and with water. The hydration chemistry is quite complex and the extent of hydration of the mineral particles is reflected in the observed properties. To promote complete and uniform hydration of this gel phase and to improve workability of the paste, as characterized by the yield stress and viscosity, polymer additives known as plasticizers and superplasticizers are added. Water- soluble plasticizers and superplasticizers differ from traditional dispersants, which commonly are used to disperse solid particles in a liquid medium, in that effective plasticizers and superplasticizers are involved in the hydration chemistries occurring at the interface between the cementitious particles and the aqueous medium.

[99] Superplasticizers are a class of anionic polymer dispersants used to inhibit aggregation in hydraulic cement, lowering the yield stress of cement pastes to improve workability and reduce water requirements. . Lignosulfonates and other forms of lignin have been used as low-cost cement plasticizers, although their performance, as assessed in measurements of reductions of water added to cement powder while still retaining the same workability, is modest. Numerous attempts have been made to improve the performance of lignosulfonates in plasticizing cement by, for example, copolymerization with synthetic water-soluble polymers, but no such modifications have significantly improved the plasticization of hydraulic cement.

[100] In a number of studies of compositions hereof, it was demonstrated that that kraft lignin can form the basis for high-performance superplasticizers in hydraulic cement. A molecular architecture based on a lignin core with a synthetic -polymer corona produced via controlled radical polymerization or CRP showed significant improvement over corona produced via free radical polymerization. Given the limited success of lignins and polymer modified lignins as plasticizers, it was unexpected that grafting water-soluble polymers to lignin using CRP methods resulted in a material capable of imparting significant improvements in cement-paste workability. Using slump tests of ordinary Portland cement slurries, it was shown that, for example, polyacrylamide-grafted lignin prepared via reversible addition-fragmentation chain transfer polymerization or RAFT can reduce the yield stress of cement paste to similar levels as a leading commercial polycarboxylate ether superplasticizer at concentrations ten-fold lower. The lignin material produced via controlled radical polymerization did not appear to reduce the dynamic viscosity of cement paste as effectively as the polycarboxylate superplasticizer, despite having a similar affinity for the individual mineral components of ordinary Portland cement. In contrast, polyacrylamide copolymerized with a methacrylated kraft lignin via conventional free radical polymerization having a similar overall composition similar to that of a number of studied the compositions hereof did not reduce the yield stress or the viscosity of cement pastes. Such results indicate that controlling the architecture of polymer-grafted lignin can significantly enhance its performance as a superplasticizer for cement.

[101] As described above, superplasticizers are a class of high-performance anionic polymers designed to modify the rheological properties of hydraulic cement. Addition of a superplasticizer reduces the yield stress of cement paste and lowers water requirements. The leading commercial superplasticizer is based on a copolymer of acrylic acid and a poly(ethylene glycol) (PEG) acrylate. Referred to as polycarboxylate ether (PCE), the superplasticizer has an anionic polymer backbone that adsorbs to ceramic particle surfaces, and the PEG side chains inhibit particle-particle aggregation through steric interactions at concentrations of 5 mg/mL.

[102] In studies of representative embodiments of superplasticizers hereof, we compared two polymer-grafted architectures based on kraft lignin and polyacrylamide and investigated their plasticization of cementitious suspensions. RAFT polymerization was used to graft acrylamide from a lignin macroinitiator, whereas free radical polymerization (FRP) was used to copolymerize acrylamide with lignin functionalized by reacting with gylcidyl methacrylate (GM). The polymer-grafted lignin materials prepared by FRP are, for example, representative of polymer-lignin composite studied previously for use with cementitious compositions with little success. These formulations were compared against PCE superplasticizer. Comparative measurements were made of solution properties, data on slump-spread measurements of yield stress, rheometer measurements of cement paste viscosity, and adsorption onto individual ordinary Portland cement (OPC) mineral components. In addition, characterization of the compressive strength of hardened Portland cement was studied to investigate the effects of these admixtures on final material properties.

[103] In several representative studies, lignin was grafted with PAm via RAFT (see Figure IB) and FRP (Figure ID). The lignin-based RAFT macroinitiator was prepared as described above (see Figure 1A) with an initiator site density of 100

lignin) (approximately 2 per lignin particle) and an average degree of polymerization of 160, resulting in a product that was 60% lignin by mass. For the comparable FRP material, lignin was reacted with GM as illustrated in Figure 1C to yield a similar initiator site density as the RAFT macroinitiator, and copolymerization of GM-lignin with acrylamide as illustrated in Figure ID yielded a product postulated to resemble crosslinked nanogels synthesized through simultaneous polymerization of mono functional and multifunctional monomers.

[104] The characteristic sizes of the materials were measured using dynamic light scattering (DLS), and representative traces are shown in Figure 6A along with the commercial PCE used for comparison. As set forth in Table 4, the RAFT-lignin-PAm had an average diameter of 35.9 nm at 0.25 mg/mL and a zeta potential of -36.2 mV. Zeta potential is a term used for electrokinetic potential in colloidal dispersions. The zeta potential (mV) can be related to the energy needed to shear a particle and its inner layer away from the outer layer/bulk medium. While the FRP-lignin-PAm had a similar zeta potential of -39.2 mV, the average diameter was 101.6 nm, consistent with the expected formation of a crosslinked aggregate of lignin and Pam. The commercial PCE had a diameter of 4.1 nm and a zeta potential of -48.9 mV, similar to previous studies of PCE. Based on these data, schematic representations of both lignin products are shown in Figure 6B (RAFT-lignin-PAm) and Figure 6C (FRP-lignin-PAm). The lignin solutions were translucent and had a light brown color, while the commercial PCE solution was dyed light green by the manufacturer.

Table 4

[105] To investigate the effects of lignin-PAm formulations on the rheological properties of hydraulic cement, slump tests, also referred to as mini-slump tests, were performed in comparison with neat OPC and OPC containing PCE at a water/cement (w/c) ratio of 0.42. Slump tests are the most common measure of hydraulic cement rheology, and are an established first method of characterizing superplasticizers. In the slump tests, cement paste is prepared using standardized mixing conditions and loaded into a metal cone or cylinder, which is raised to allow the cement to flow until the yield stress exceeds the shear stress. The experimental parameters recorded are the change in height and diameter from the original shape. While the complex phenomenon of cement flow is captured in only two geometric parameters, slump tests have the advantage of high levels of reproducibility when conditions are carefully controlled. Representative pictures of the slumps are shown in Figure 7A through 7D. Figure 7A is an enhanced view of the scale used for slump test with the RAFT- lignin-PAm sample. Figure 7B illustrates a slump test at 0.42 w/c ratio showing diameter and height for Portland Cement. Figures 7C illustrates a slump test at 0.42 w/c ratio showing diameter and height for PCE (0.05 wt%). Figures 7D illustrates a slump test at 0.42 w/c ratio showing diameter and height for RAFT-lignin-g-PAm (0.05 wt%).

[106] The slump spread as a function of superplasticizer concentration is presented graphically in Figure 8A. When compared to commercial PCE, RAFT-lignin-PAm results in almost comparable increases in spread but performs significantly better at lower concentrations. For example, at 0.025 wt%, the spread is anywhere from 20-30 mm larger than PCE or neat Portland cement. The slump spread is a more gradual function of RAFT lignin-PAm concentration whereas PCE experiences a steep increase at a concentration around 0.175%. In contrast, FRP lignin-PAm has only very modest effects on the slump spread of OPC, suggesting this grafting architecture does not result in effective dispersants. Figure 8B illustrates slump spread as a function water content at a superplasticizer concentration of 0.05 wt% for Portland cement, PCE, and RAFT-lignin-PAm, demonstrating that the polymer-grafted lignins hereof outperform PCE at low concentrations. Figure 8C illustrates slump spread as a function water content at a superplasticizer concentration of 0.1 wt% for Portland cement, PCE, and RAFT-lignin-PAm.

[107] In slump tests, cement pastes flow until the yield stress exceeds the shear stress, and analytical modeling provides a functional relationship between the slump spread R and the shear stress το. When surface tension effects are ignored and an oblong initial geometry is assumed, the shear stress takes the form

where p is the paste density, g is the gravitational constant, and V is the volume. Using this equation, the yield stress of OPC at w/c of 0.42 is calculated to be 236.3±15.3 Pa while that containing 2.7 mg/mL of RAFT lignin-PAm was 31.8±6.2 Pa compared to 20.6±5.4 Pa for PCE at the same concentration. From these values it is concluded that even small increases in slump spread stem from significant decreases in yield stress.

[108] To further investigate changes in rheological properties of cement pastes, oscillatory rheometry experiments were performed to measure changes in viscosity η' under a strain-magnitude sweep at a constant shear rate of 0.01 rad/s using a vane fixture to prevent slip at the rheometer interface. These experiments were designed to probe the viscous response of cement pastes as the colloidal gel network was gradually disrupted under increasing oscillatory strain. The viscoelasticity of cement paste has been shown to depend strongly on the state of dispersion, with Newtonian behavior observed for higher w/c ratio and superplasticizer concentrations, but complex thixotropic behavior is observed otherwise.

[109] Figures 9A and 9B shows η' for cement pastes (w/c = 0.42) at superplasticizer concentrations of 0.05 wt.% and 0.1 wt.%, respectively, which are near the transition at which PCE provided a significant increase in slump spread as a function of concentration. Shear thinning was observed for all formulations from oscillatory strains of 0.05% to 50%. At superplasticizer concentrations of 0.05 wt%, neat OPC had the highest viscosity at 0.05% strain at 581 Pa-s, but the range of low-shear viscosity values was relatively low. In contrast, at 0.10 wt% superplasticizer, the cement paste containing FRP-lignin-PAm had a viscosity at 0.05% strain of 960 Pa-s while that containing PCE had a value of 190 Pa-s. The 0.05%-strain viscosity for the RAFT-lignin-PAm sample had a value of 441 Pa-s. RAFT-lignin-PAm thus led to significant reductions in yield stress as observed in slump tests and reduced viscosity.

[110] To further study the interactions of these superplasticizers with cement particles, adsorption experiments were performed using individual OPC mineral components. The result of such studies are summarized in Figure 10. Adsorption experiments were performed in 0.5% solutions of superplasticizer containing 5 wt% mineral, and results are reported as % superplasticizer adsorbed to each mineral phase normalized to the BET surface areas. Figure 10 sets forth adsorption data for the studied superplasticizers at different concentrations for cement phases normalized to the BET surface area of each mineral (reported parenthetically in m²/g along with the zeta potential value) wherein (a) dicalcium silicate (C2S) (BET = 0.9845 ± 0.0099 m²/g; ζ = -5.96 ± 0.42 mV); (b) tricalcium silicate (CsS) (BET = 0.8252 ± 0.0047 m²/g; ζ = -7.77 ± 0.32 mV); (c) tricalcium aluminate (C3A) (BET = 0.3492 ± 0.0133 m²/g; ζ = +3.23 ± 0.44 mV); and (d) tetracalcium aluminoferrite (C₄AF) (BET = 0.5797 ± 0.0017 m²/g; ζ = +26.35 ± 1.46 mV). Zeta-potential measurements are also included for comparison. Results from the zeta-potential measurements are consistent with literature values.

[Ill] OPC clinker is composed of the calcium silicates C2S and C3S, and the calcium aluminates C3A and C₄AF. The silicates have weak anionic charge while the aluminates are cationic. Commercial superplasticizers have a negative charge that promotes avid adsorption to C3A and C₄AF, but adsorption onto the silicate phases has been demonstrated, which can be attributed in part to the high ionic strength (ca. 0.1 M) of the cement fluid phase.

[112] PCE had the strongest adsorption across all phases, which is consistent with its high dispersant capabilities. FRP-lignin-PAm had comparable adsorption to aluminate phases as PCE but much weaker adsorption to silicate phases. RAFT-lignin-PAm had adsorption affinity to silicate phases that was similar to PCE but the interaction was significantly weaker to aluminate phases, especially to C₄AF, which had the highest positive zeta potential in solution. However, commercial OPC generally has C3S content ranging from 55-65%, so effective interactions with this component are essential for superplasticizer function, and these interactions were observed for RAFT-lignin-PAm.

[113] The PCE and FRP-lignin-PAm trends essentially track with the polymer zeta potentials (-48.9 mV and -39.2 mV, respectively), although adsorption of the latter to the cationic aluminate phases was stronger than expected. However, the RAFT-lignin-PAm results are not predicted based on a zeta potential of -36.2 mV. Interactions of RAFT-lignin- PAm with neutral/anionic silicate species are stronger than those of FRP-lignin-Pam, but interactions with the highly cationic C₄AF are significantly weaker. These trends indicate that lignin interactions that are not determined strictly by Coulombic forces between polymers and particle surfaces.

[114] To provide an assessment of the effects of PAm-grafted kraft lignin on the setting process, compressive strengths were measured for samples at 7 days, the time point at which cement should exhibit basic structural characteristics, as well as 28 days. Lignosulfonates are known to retard the hydration reactions that occur in cement setting, and trade-offs are associated between fluidity and compressive strength with this class of lignin plasticizer. The results are shown in Figure 11. The compressive strengths of samples containing at w/c ratio of 0.42 and containing 0.05% superplasticizers are all similar at 7 days and 25% higher than for neat OPC. The results at 7 days and 28 days indicate that RAFT-lignin-PAm does not interfere with these processes. In general, the results of non-optimized studies with OPC indicate that RAFT-lignin-PAm is an effective superplasticizer capable of significantly reducing the yield stress of cement paste and reducing the low-strain viscosity.

[115] The representative studies hereof focused on kraft lignin because of its good solubility in polar solvents, which provides for facile RAFT polymerizations. This approach may also be extended to lignosulfonates, when grafted with polymer via CRP as described herein. Lignosulfonates may perform more effectively than kraft lignin with carboxylate groups.

[116] Controlled radical polymerization provides access to polymer-grafted lignin architectures that are distinct from those prepared by FRP or condensation polymerization. While this basic architecture appears to offer significant performance enhancements as a superplasticizer, polymer composition, grafting density and/or degree of polymerization may be further optimized for use in cement applications. In addition, utilization of sulfonate or carboxylate monomers in the grafts may further tune interactions between ceramic particles and test whether the mechanism involves inducing the formation of weak floes in cementitious suspensions. Grafting density may also be used to tune adsorption strength with a similar competition between charge density and polymer-graft density as observed in PCE.

[117] The results of the present studies demonstrate that high-performance cement dispersants are obtained through a grafted architecture using CRP of acrylamide from a lignin macroinitiator, whereas copolymerization of acrylamide with a functionalized lignin resulted in a nanogel that had similar particle size and charge but lacked the dispersant performance. Significant reductions in OPC yield stress are reported at lignopolymer concentrations 10- fold lower than a commercial PCE superplasticizer. Trends in adsorption onto OPC mineral components indicate that the chemistry of kraft lignin influences the affinity of RAFT-lignin- PAm for cementitious particles compared to PCE, so that the plasticization mechanism is not based entirely on steric inhibition of aggregation. The results demonstrate that controlled radical polymerization chemistry is an important tool in synthesizing technologically useful lignin-based superplasticizers, and these materials have excellent potential as a next- generation admixture for hydraulic cement.

[118] Global production of hydraulic cement in 2012 was 3.7 billion tons, making this a potentially important application of lignin materials hereof. The lignin-based systems, methods and compositions hereof may also be used as dispersants for other applications such as, but not limited to, petroleum or natural gas recovery, inkjet printing, cosmetics, and/or personal care products.

[119] Experimental

[120] Materials.

[121] Kraft lignin was purchased from TCI America and was acidified and dried prior to use as described previously. A commercial PCE (ADVA® 190 available from Grace Construction Chemicals of W.R. Grace and Company of Columbia, Maryland) was provided by Grace Construction Chemicals and used as received. DMF, acetone (American Chemical Society (ACS) reagent grade) and hexanes (a mixture of C6H14 isomers as well as methylcyclopentane; ACS reagent grade) were purchased from Pharmco Aaper of Brookfield, Connecticut. Tetrahydrofuran (THF), azobisisobutyronitrile (AIBN), potassium hydroxide, hydrochloric acid, sodium phosphate, sodium azide, acrylamide, acrylic acid, potassium xanthate, 2-bromopropionic acid, methylene chloride, potassium carbonate, and pentafluorobenzaldehyde (PFB) were purchased from Sigma-Aldrich, Inc. of St. Louis, Missouri. Lignin was neutralized with 0.1 M HC1 solution, washed with deionized water then diethyl ether, and dried under vacuum for 24 h. Acrylamide was passed through a alumina column before use to remove inhibitors, and acrylic acid was purified by vacuum distillation. All other chemicals were used as received.

[122] Preparation of lignin RAFT macroinitiator. Potassium xanthate (14.1 g, 88 mmol) was reacted with 2-bromopropionic acid (5.36 mL, 59.5 mmol) in dry THF at room temperature for 24 h to yield the xanthate carboxylic acid. This was reacted with 1 molar equivalent of thionyl chloride in dry THF to yield the acyl chloride xanthate, which was then reacted with lignin at room temperature for 12 h to yield the RAFT macroinitiator. To make the lower grafting density 8 g of acidified lignin was used for 0.5 g of xanthanate carboxylic acid and for the higher grafting density 2 g of acidified lignin was used. The degree of xanthate functionalization was quantified using ^XH NMR on a Bruker 300 AVANCE™ spectrometer (available from Bruker Corporation of Billerica, Massachusetts) using PFB as an internal standard to convert proton intensities to initiator concentration in units of

lignin).

[123] Preparation of polymer-grafted lignin. RAFT was used to prepare polymer- grafted kraft lignin. The RAFT macroinitiator (0.1 g) along with AIBN (0.005 g, 0.03 mmol) was added to monomer (0. 3 g, 4 mmol) in DMF (4 mL). The flask was then sealed with a rubber stopper and was degassed using 2 for 30 minutes while stirring at room temperature and finally immersed in an oil bath at 70 °C. The target conversion of 98% was measured using ^XH NMR which was reached in 24 h for both monomers. The solution was precipitated into hexanes, filtered, washed with CH2CI2 and then placed under vacuum at 45 °C overnight.

[124] Polymer-graft cleavage and analysis. To assess the molecular weight distribution of the polymer grafts, 0.2 Lignin676PAml00 was dissolved in KOH solution (0.1 g in 1 mL water) and heated at 70 °C for 12 h. Under these conditions, hydrolysis of the ester linkage between kraft lignin and PAm cleaves the grafted material. Following neutralization with HCl, the solution was precipitated into diethyl ether, dried in air and the ungrafted PAm was extracted with CH2CI2. The solvent was removed under vacuum and the extracted material was resuspended in solution for analysis by ^XH NMR and gel permeation chromatography using an Alliance 2695 Separations Module using water, which contained 0.1 M sodium phosphate buffer and 0.01% NaN3, as the eluent at room temperature with a flow rate of 1 mL/min.

[125] Dynamic light scattering. Size distributions of particles were measured in an aqueous solution at a concentration of 1 mg/mL. The solution was ultrasonicated for 2 minutes prior to being placed in the glass cuvette. The particle diameter was measured using a ZETASIZER® DLS (available from Malvern Instruments Limited Company of Worcestershire, United Kingdom).

[126] Surface tension measurements. Surface tension of aqueous solutions at a variety of concentrations was measured using a De Nouy ring-type tensiometer (available from Kruss Gmbh of Hamburg, Germany) at 25 °C. The De Nouy ring was first calibrated against a known mass and then DI water prior to use. A minimum of six measurements per sample was recorded and the average and standard deviation values were reported. [127] Viscosity measurements. Viscosity of aqueous solutions was measured using a Brookfield cone-and-plate viscometer (available from Brookfield Engineering Laboratories of Middleboro, Massachusetts). The steady-shear measurements were taken at a rotational rate of 100 rpm.

[128] Emulsification tests. Polymer-grafted lignin was dissolved into deionized water and mixed with hexanes using an ultrasonicator (a MISONIX™ S-4000 sonicator available from Qsonica, LLC of Newtown, Connecticut) at pulsing amplitude of 70% and power of 85 W. Each sample was ultrasonicated for 3 min and then allowed to equilibrate. The percentage of the lignin in the emulsion phase was then measured after 24 h by measuring the absorbance at 290 nm using a CARY® 300 Spectrophotometer (available from Agilent Technologies of Santa Clara, California) and comparing this value that of the starting aqueous solution.

[129] Cement Studies.

[130] Preparing the lignin-acrylamide copolymer via CRP and FRP. RAFT was used to synthesize polymer-grafted kraft lignin via CRP. The RAFT macroinitiator was synthesized as described above. For preparing the lignin-acrylamide copolymer via free radical polymerization (FRP), kraft lignin was first functionalized by reacting with GM through the epoxide ring. The lignin-GM macromonomer along with AIBN (0.005 g, 0.03 mmol) was added to acrylamide (0.3 g, 4 mmol) in DMF (4 mL). The flask was then sealed with a rubber stopper and was degassed using N2 for 30 min while stirring at room temperature and finally immersed in an oil bath at 70 °C. Following polymerization for 1 h, the solution was precipitated into hexanes, filtered, washed with CH2CI2, and then placed under vacuum at 45 °C overnight.

[131] Preparation of individual components of OPC. Individual mineral components of OPC were prepared through solid-state or sol-gel reactions. Dicalcium silicate (C2S) powder was prepared by combining CaCC and S1O2 in stoichiometric amounts. The powder was ball milled for 24 hours and then calcined at 1500 °C for 24 hours._Tricalcium silicate (C3S) powders were prepared using a sol-gel synthesis in which 0.5 mol of Si(OC2Hs)4 was mixed with 0.05 wt.% of nitric acid as a catalyst which was then added to 200 mL of deionized water. Then 1.5 mol of Ca(N03)2.4H20 was subsequently added while stirring. The solution was then maintained at 60 °C until gelation occurred and then was dried at 120 °C for four hours. The final product was then calcined at 1450 °C for 8 hours. Tetracalcium aluminoferrite (C₄AF) powders were synthesized by adding CaC03, AI2O3 (Alumina) and Fe203 (Iron (III) oxide) in stoichiometric amounts. The powder was ball milled for 24 hours and then calcined at 1350 °C for 24 hours. Tricalcium aluminate (C3A) powders were synthesized using the modified Pechini method using Ca( 03)2.4H20 (26.239 g) and (Α1( θ3)3 ·9Η2θ (aluminum nitrate nanohydrate, 27.787 g), which were dissolved in 45 mL of ethanol to obtain a CaO/AkC molar ratio of 3. Citric acid was added such that molar ratio citric acid: total cations is 1 : 1. The mixture was stirred until a clear solution was obtained and then ethylene glycol was added to obtain a molar ratio of ethylene glycohcitric acid of 2: 1. The solution was stirred at 80 °C for 24 h, until the formation of a viscous gel. The gel was then thermally treated at 150 °C for 24 h and formed a brown resin-type precursor. The precursor was calcined at 600 °C for 2 h and then 1300 °C for 4 h and 1350 °C for 1 h. The final products for each phase were characterized using X-Ray diffraction (X'Pert Pro Multipurpose Diffractometer (MPD) available from PANalytical of Westborough, Massachusetts) using a continuous scan from 5° to 65° at a scan speed of 0.75°/min.

[132] Solution property measurements. Surface area for each phase was measured using the Brunauer-Emmett-Teller (BET) method using a Gemini VII Micrometrics surface area analyzer (available from Micrometrics of Norcross, Georgia). Each sample was degassed for 24 hours at 60 °C prior to being analyzed.

[133] Zeta potential and size distribution for each phase was measured in an aqueous solution at a concentration of 1 mg/mL. The zeta potential and particle diameter were measured using a ZETASIZER as described above (available from Malvern Instruments).

[134] Adsorption of the different samples onto each cement phase was measured by analyzing the total amount of carbon left in the sample before and after adsorption. Each sample was mixed with the phase at 5 different concentrations (0.25, 0.5, 1, 2 and 4 mg/mL) for an hour and then centrifuged to obtain the top layer. The top layer was subsequently diluted and the total organic carbon content was measured using a GE InnovOX TOC analyzer (available from General Electric Company of Boulder, Colorado).

[135] Rheological and compressive strength measurements. Slump tests were used to gauge changes in yield stress of cement pastes. Samples were prepared using a HOBART® mixer (available from Hobart of Troy, Ohio) and were agitated for 3 minutes at w/c ratio of 0.42 prior to being packed in a mini-slump cylinder, which was 3 cm in diameter. The cylinder was slowly lifted and diameters along two orthogonal directions were recorded and used to calculate the slump spread and relative flow area ratio. The slump height was also measured as an additional measure of cement flow.

[136] Rheometric measurements on cement pastes were performed with a DHR Rheometer (TA Instruments of New Castle, Delaware) using a vane fixture to assess changes in paste viscosity. An oscillatory strain sweep was performed on the samples at a constant frequency of 1 Hz for samples with a w/c ratio of 0.42.

[137] The compressive strength of each sample was tested at 7 days. Ten samples for each superplasticizer were tested and compared to OPC. The samples were prepare by adding 200 g of cement along with superplasticizers dissolved in water to create a 0.42 w/c ratio at 0.05 wt% polymer. The slurry was agitated using a HOBART mixer for three minutes and then poured into a 2"x2" plastic mold from Deslauriers, Inc. of LaGrange Park, Illinois. The samples were allowed to cure for 7 days at room temperature and 100% humidity then tested on a CM-2500 compression testing machine available from Testmark Industries of East Palestine, Ohio.

[138] The foregoing description and accompanying drawings set forth a number of representative embodiments at the present time. Various modifications, additions and alternative designs will, of course, become apparent to those skilled in the art in light of the foregoing teachings without departing from the scope hereof, which is indicated by the following claims rather than by the foregoing description. All changes and variations that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

WHAT IS CLAIMED IS:

1. A method of plasticizing cement, comprising: including a polymer-grafted lignin in a mixture of cement and water, the polymer-grafted lignin being formed by grafting at least a first polymer with lignin, the at least a first polymer being formed via a controlled radical polymerization, the at least a first polymer being selected so that the polymer-grafted lignin is soluble in an aqueous fluid.

2. The method of claim 1 wherein the at least a first polymer is a hydrophilic polymer.

3. The method of claim 2 wherein the at least a first polymer has a degree of polymerization in the range of 10 to 1000.

4. The method of claim 2 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.1592 grafts per nm².

5. The method of claim 2 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.0398 grafts per nm².

6. The method of claim 2 wherein the graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.00796 grafts per nm².

7. The method of claim 2 wherein the at least a first polymer is grafted from the lignin.

8. The method of claim 2 wherein the first at least a polymer is grafted to the lignin.

9. The method of claim 2 wherein the at least a first polymer is a poly(acrylamide), a poly(acrylic acid), a 2-acrylamido-2-methyl-N-propane sulfonate polymer or an oligoethylene oxide methacrylate polymer .

10. The method of claim 2 wherein the at least a first polymer is formed from a monomer selected from the group consisting of, an acrylic acid monomer, an acrylamide monomer, or an acrylate monomer.

1 1. The method of claim 2 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of an acrylic acid monomer, a methacrylic acid monomer, an acrylamide monomer, a methacrylamide monomer, an acrylate monomer or a methacrylate monomer.

12. The method of claim 2 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of acrylic acid, acrylamide, hydroxyethyl acrylate, oilgoethylene acrylate, butyl trimethyl ammonium chloride acrylate, butyl trimethyl ammonium bromide acrylate, hydroxyethyl methacrylate, butyl trimethyl ammonium chloride methacrylate, and butyl trimethyl ammonium bromide methacrylate.

13. The method of claim 2 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.001 to 10 wt%.

14. The method of claim 2 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 10 wt%.

15. The method of claim 2 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 2 wt%.

16. The method of claim 2 wherein the polymer grafted lignin is included in the mixture of cement and water in a concentration less than 2 wt%.

17. The method of claim 2 wherein the lignin comprises a kraft lignin or a lignosulfonate.

18. A cementitious composition, comprising: a polymer-grafted lignin, cement and water, the polymer-grafted lignin being formed by grafting at least a first polymer with lignin, the at least a first polymer being formed via a controlled radical polymerization, the at least a first polymer being selected so that the polymer-grafted lignin is soluble in an aqueous fluid.

19. The cementitious composition of claim 18 wherein the at least a first polymer is a hydrophilic polymer.

20. The cementitious composition of claim 19 wherein the at least a first polymer has a degree of polymerization in the range of 10 to 1000.

21. The cementitious composition of claim 19 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.1592 grafts per nm².

22. The cementitious composition of claim 19 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.0398 grafts per nm².

23. The cementitious composition of claim 19 wherein the graft density of the at least a first polymer on the lignin is per unit surface area in the range of 0.000159 to 0.00796 grafts per nm².

24. The cementitious composition of claim 19 wherein the at least a first polymer is grafted from the lignin.

25. The cementitious composition of claim 19 wherein the first at least a polymer is grafted to the lignin.

26. The cementitious composition of claim 19 wherein the at least a first polymer is a poly(acrylamide), a poly(acrylic acid), a 2-acrylamido-2-methyl-N-propane sulfonate polymer or an oligoethylene oxide methacrylate polymer .

27. The cementitious composition of claim 19 wherein the at least a first polymer is formed from a monomer selected from the group consisting of, an acrylic acid monomer, an acrylamide monomer, or an acrylate monomer.

28. The cementitious composition of claim 19 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of an acrylic acid monomer, a methacrylic acid monomer, an acrylamide monomer, a methacrylamide monomer, an acrylate monomer or a methacrylate monomer.

29. The cementitious composition of claim 19 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of acrylic acid, acrylamide, hydroxyethyl acrylate, oilgoethylene acrylate, butyl trimethyl ammonium chloride acrylate, butyl trimethyl ammonium bromide acrylate, hydroxyethyl methacrylate, butyl trimethyl ammonium chloride methacrylate, and butyl trimethyl ammonium bromide methacrylate.

30. The cementitious composition of claim 19 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.001 to 10 wt%.

31. The cementitious composition of claim 19 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 10 wt%.

32. The cementitious composition of claim 19 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 2 wt%.

33. The cementitious composition of claim 19 wherein the polymer grafted lignin is included in the mixture of cement and water in a concentration less than 2 wt%.

34. The cementitious composition of claim 19 wherein the lignin comprises a kraft lignin or a lignosulfonate.

35. A composition, comprising: at least one liquid phase, a surfactant suitable to lower the surface tension at a liquid-liquid or a liquid-gas phase boundary, the surfactant being formed by grafting at least a first polymer with lignin, the at least a first polymer being formed via a controlled radical polymerization, the at least a first polymer being selected so that the surfactant is soluble in the at least one liquid phase.

36. The composition of claim 35 wherein the surfactant is an emulsifier in the composition or the surfactant is a foaming agent in the composition.

37. The composition of claim 36 wherein the at least a first polymer is a hydrophilic polymer or a hydrophobic polymer.

38. The composition of claim 36 wherein the at least a first polymer has a degree of polymerization in the range of 10 to 1000.

39. The composition of claim 36 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.1592 grafts per nm².

40. The composition of claim 36 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.0398 grafts per nm².

41. The composition of claim 36 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.00796 grafts per nm².

42. The composition of claim 36 wherein the at least a first polymer is grafted from the lignin.

43. The composition of claim 36 wherein the first at least a polymer is grafted to the lignin.

44. The composition of claim 36 wherein the at least a first polymer is a poly(acrylamide), a poly(acrylic acid), a 2-acrylamido-2-methyl-N-propane sulfonate polymer or an oligoethylene oxide methacrylate polymer .

45. The composition of claim 36 wherein the at least a first polymer is formed from a monomer selected from the group consisting of, an acrylic acid monomer, an acrylamide monomer, or an acrylate monomer.

46. The composition of claim 36 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of an acrylic acid monomer, a methacrylic acid monomer, an acrylamide monomer, a methacrylamide monomer, an acrylate monomer or a methacrylate monomer.

47. The composition of claim 36 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of acrylic acid, acrylamide, hydroxyethyl acrylate, oilgoethylene acrylate, butyl trimethyl ammonium chloride acrylate, butyl trimethyl ammonium bromide acrylate, hydroxyethyl methacrylate, butyl trimethyl ammonium chloride methacrylate, and butyl trimethyl ammonium bromide methacrylate.

48. The composition of claim 36 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.001 to 10 wt%.

49. The composition of claim 36 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 10 wt%.

50. The composition of claim 36 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 2 wt%.

51. The composition of claim 36 wherein the polymer grafted lignin is included in the mixture of cement and water in a concentration less than 2 wt%.

52. The composition of claim 35 wherein the surfactant is a foaming agent in the composition.

53. The composition of claim 35 wherein the surfactant is an emulsifier in the composition.

54. The composition of claim 53 wherein the at least one liquid phase is an aqueous emulsion phase and the composition further comprises at least a second liquid phase which is an oleophilic phase.

55. The composition of claim 53 wherein the at least one liquid phase is an oleophilic emulsion phase and the composition further comprises at least a second liquid phase which is an aqueous phase.

56. The composition of claim 53 wherein the surfactant is adapted to stabilize an aqueous/oleophilic emulsion.

57. The composition of claim 35 wherein the lignin comprises a kraft lignin or a lignosulfonate.

58. A method of lowering a surface tension at a liquid-liquid or a liquid-gas phase boundary in a composition including a first liquid phase, comprising: adding a surfactant adapted to lower the surface tension, the surfactant being formed by grafting at least a first polymer with lignin, the at least a first polymer being formed via a controlled radical polymerization, the at least a first polymer being selected so that the surfactant is soluble in the first liquid phase.

59. The method of claim 58 wherein the surfactant is an emulsifier in the composition or the surfactant is a foaming agent in the composition.

60. The method of claim 59 wherein the at least a first polymer is a hydrophilic polymer or a hydrophobic polymer.

61. The method of claim 59 wherein the at least a first polymer has a degree of polymerization in the range of 10 to 1000.

62. The method of claim 59 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.1592 grafts per nm².

63. The method of claim 59 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.0398 grafts per nm².

64. The method of claim 59 wherein the average graft density of the at least a first polymer on the lignin per unit surface area is in the range of 0.000159 to 0.00796 grafts per nm².

65. The method of claim 59 wherein the at least a first polymer is grafted from the lignin.

66. The method of claim 59 wherein the first at least a polymer is grafted to the lignin.

67. The method of claim 59 wherein the at least a first polymer is a poly(acrylamide), a poly(acrylic acid), a 2-acrylamido-2-methyl-N-propane sulfonate polymer or an oligoethylene oxide methacrylate polymer .

68. The method of claim 59 wherein the at least a first polymer is formed from a monomer selected from the group consisting of, an acrylic acid monomer, an acrylamide monomer, or an acrylate monomer.

69. The method of claim 59 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of an acrylic acid monomer, a methacrylic acid monomer, an acrylamide monomer, a methacrylamide monomer, an acrylate monomer or a methacrylate monomer.

70. The method of claim 59 wherein the at least a first polymer is formed from a monomer selected from the groups consisting of acrylic acid, acrylamide, hydroxyethyl acrylate, oilgoethylene acrylate, butyl trimethyl ammonium chloride acrylate, butyl trimethyl ammonium bromide acrylate, hydroxyethyl methacrylate, butyl trimethyl ammonium chloride methacrylate, and butyl trimethyl ammonium bromide methacrylate.

71. The method of claim 59 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.001 to 10 wt%.

72. The method of claim 59 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 10 wt%.

73. The method of claim 59 wherein the polymer grafted lignin is included in the mixture of cement and water in the range of 0.025 to 2 wt%.

74. The method of claim 59 wherein the polymer grafted lignin is included in the mixture of cement and water in a concentration less than 2 wt%.

75. The method of claim 58 wherein the surfactant is a foaming agent in the composition.

76. The method of claim 58 wherein the surfactant is an emulsifier in the composition.

77. The method of claim 76 wherein the at least one liquid phase is an aqueous emulsion phase and the composition further comprises at least a second liquid phase which is an oleophilic phase.

78. The method of claim 76 wherein the at least one liquid phase is an oleophilic emulsion phase and the composition further comprises at least a second liquid phase which is an aqueous phase.

79. The method of claim 77 wherein the surfactant is adapted to stabilize an aqueous/oleophilic emulsion.

80. The method of claim 58 wherein the lignin comprises a craft lignin or a lignosulfonate.