WO2014151592A1 - Formaldehyde-free finishing of fabric materials - Google Patents

Abstract

The present invention provides methods for preparing a cross-linked fabric material, wherein the method comprises treating a fabric material comprising a polysaccharide usable for fabric with an aqueous solution of a carboxylic acid or an anhydride of the multifunctional carboxylic acid; and curing the fabric material, resulting in cross-linking of the polysaccharide by the carboxylic acid or the anhydride.

Description

FORMALDEHYDE-FREE FINISHING OF FABRIC MATERIALS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 61/799,811, filed March 15, 2013, the teachings of which are incorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

[0002] Wrinkle-free treatment of cotton fabrics is generally achieved by chemically crosslinking cotton cellulose by using traditional formaldehyde containing N-methylol compounds or non-formaldehyde 1,2,3,4-butanetetracarboxylic acid (BTCA) (Montazer, M., and Afjeh, M. G., Journal of ^'Applied Polymer Science, 103, 178-185(2007); Yang, C. Q. and Wei, W., Textile Research Journal, 70, 143-147 (2000); E. Yang, C. Q. and Wei, W., Textile Research Journal, 70, 230-236 (2000); Ibrahim, N. A. et al., Journal of Applied Polymer Science, 84, 2243-2253). The ultraviolet (UV) protective functions on the fabrics, which is important for protecting both materials and wearers (Gouda, M., and Keshk, S. M. A. S., Carbohydrate

Polymers, 80, 504-512 (2010); Lu, FL, Fei et al., Journal of Colloid and Interface Science, 300, 111-116 (2006)), can be obtained by incorporating UV absorbents or UV blockers onto the fabric (Czajkowski, W. et al. Dyes and Pigments, 71, 224-230 (2006); Ibrahim, N. A. et al.,

Carbohydrate Polymers, 79, 839-846 (2010); Wang, Q., and Hauser, P. J., Carbohydrate Polymers, 81, 491-496 (2010); Ibrahim, N. A. et al., Polymer-Plastics Technology and

Engineering, 46, 905-911 (2007); Hou, A., Zhang, C, and Wang, Y., Carbohydrate Polymers, 87, 284-288 (2012)). To obtain both functions, multi-step chemical treatments of cotton fabrics should be carried out, which could consume large quantity of water and energy and consequently increase costs and environmental impacts. Thus, development of energy efficient multi- functional finishing processes of textiles is extremely important.

[0003] In previous research, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPTCD) was directly incorporated into cotton cellulose by using Ν,Ν-dimethylformamide (DMF) as a solvent (Hong, K. H., and Sun, G., Carbohydrate Polymers, 84, 1027-1032 (2011)). The results proved that the BPTCD could crosslink with cellulose, and the benzophenone group could introduce photo-active antimicrobial functions to the products. However, due to the use of DMF as a solvent, the treatment process is not practical to textile industry. Since the two anhydride groups in BPTCD could be hydrolyzed to tetracarboxylic acids, which will make the compound, benzophenone tetracarboxylic acid (BPTCA) soluble in hot water, direct use of BPTCD aqueous solutions as finishing baths of cotton fabrics is possible. Thus, a process of using hydrolyzed BPTCD in aqueous solutions in treatment of cotton fabrics was developed, and the process was successful and industrially practical. Based on the well-recognized reaction mechanism of polycarboxylic acids in crosslinking cellulose, the polycarboxylic acids should form anhydrides on cotton which then can form ester bonds with cellulose (Yang, C. Q., Journal of Polymer Science Part A: Polymer Chemistry, 31, 1187-1193 (2003); Yang, C. Q., and Wang, X., Textile Research Journal, 66, 595-603 (1996)). Thus, the benzophenone tetracarboxylic acid should form BPTCD again on cellulose, and an esterification reaction occurs between the anhydride and hydroxyl groups on cellulose consequently under elevated temperatures. However, the results obtained in the BPTCD treatment of cotton fabrics revealed that the polycarboxylic acids in the system could directly react with hydroxyl groups under the catalyst, sodium hypophosphite, and form ester bonds without going through the formation of anhydride. To further prove and understand the overall reactions of the benzophenone tetracarboxylic acid on cellulose, FTIR spectrometer, differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) were employed in the structural analysis of the materials.

[0004] Clothing has been considered and actually has acted in many aspects as a "second skin" or a protective outer layer to humans. Real human skin is the largest organ that has various protective functions against almost all natural hazards. In certain instances, it is possible to impart protective functions onto clothing materials, the new products are similar to a second skin to wear. Based on general expectations, such clothing materials should at least possess multifunctional properties including comfort, easy-care, moisture and heat regulating, self- cleaning against biological and chemical toxins, sun or UV-protective functions. To obtain multiple functions, multi-step chemical treatments of cotton fabrics should be conducted, which could consume large quantity of water and energy and consequently increase costs and environmental impacts. Thus, development of energy efficient multi-functional finishing processes of textiles is extremely important (Ibrahim, N. A., Journal of Industrial Textiles, 39, 233-265 (2010)).

[0005] In a previous research, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPTCD) was incorporated into cotton cellulose by using Ν,Ν-dimethylformamide (DMF) as a solvent (Hong, K. H., and Sun, G., Carbohydrate Polymers, 84, 1027-1032 (201 1)). The results proved that the BPTCD could react with cellulose, and the benzophenone group could provide photoactive functions. Due to the use of DMF as a solvent, the treatment process is costly on a large scale.

[0006] In view of the foregoing, there is a need to find new and improved ways to cross-link polycarbohydrate compositions (e.g. , cellulose, such as cotton). Methods of cross-linking polycarbohydrate compositions are needed with a multifunctional carboxylic acid or anhydride without the use of an aprotic solvent. The present invention provides these and other needs.

BRIEF SUMMARY OF THE INVENTION

[0007] Manufacturers and designers of textile goods and garments have long sought the application of effective durable press wrinkle-free coatings to cellulosic-based textiles.

Traditional durable press finishes involve the use of formaldehyde or formaldehyde derivatives as the cross-linking agent. Despite significant drawbacks, formaldehyde cross-linking agents have long remained the industry standard due to their effectiveness and inexpensive price. The current invention provides new and improved methods for cross-linking.

[0008] As such, the present invention relates to cross-linked polycarbohydrate compositions (e.g. , cellulose, such as cotton) and methods of making the same, preferably methods that do not require the use of an aprotic solvent. More particularly, some embodiments relate to fabric materials and methods of cross-linking them with an aromatic carboxylic acid or anhydride (e.g. , 3,3',4,4'-benzophenone tetracarboxylic acid or dianhydride) without the use of N,N- dimethylformamide (DMF). In some instances, thearomatic carboxylic acid or anhydride is multifunctional.

[0009] Aromatic carboxylic acids can react with cellulose to form ester bonds and cross-link cellulose, and such a cross-linking reaction provides wrinkle-free functions on cellulose- containing fabrics. Certain aromatic carboxylic acids can directly react with cellulose to form ester bonds without formation of anhydrides, crosslinking the fabric material. Direct

esterification is beneficial as the reaction can be conducted at lower temperatures and more efficiently. The application of 3,3',4,4'-benzophenone tetracarboxylic acid onto cotton fabrics at elevated temperature (e.g., 160 °C) with or without a catalyst is a good example of the chemistry. The treated fabrics using the methods herein are durable, wrinkle-free, and have very good mechanical, bacterial static and UV-protective properties. In certain instances, the methods include an aromatic carboxylic acid reacting with the fabric material comprising a

polysaccharide to form an ester bond directly without formation of an anhydride to crosslink the fabric material. The present invention also includes the fabric produced by such methods.

[0010] In one embodiment, the present invention provides a method for preparing a cross-linked fabric material, the method comprising, consisting essentially of, or consisting of:

treating a fabric material comprising a polysaccharide usable for fabric with an aqueous solution of an aromatic carboxylic acid or an anhydride of the aromatic carboxylic acid; and

curing the fabric material, resulting in cross-linking of the polysaccharide by the aromatic carboxylic acid or the anhydride. In certain aspects, the method is substantially free of formaldehyde, paraformaldehyde, and N,N-dimethyl formamide (DMF). In certain instances, the method is completely free of formaldehyde. [0011] In another embodiment, the present invention provides a fabric material product prepared by the methods described herein.

[0012] In yet another embodiment, the present invention provides a fabric material substrate for a curing reaction, wherein the fabric material substrate includes a polysaccharide, an aromatic carboxylic acid, and optionally water. [0013] In certain instances, the processes herein produce textiles which are wrinkle free. In other instances, the processes herein impart one or more of the following functionalities: i) wrinkle-free; ii) UV protection; iii) antimicrobial function; and iv) self-cleaning or

decontamination through the storage of the hydrogen peroxide provided by light. In addition, the processes described are useful for wood pulp, wood adhesives, cellulose fibers, such as blended textiles, paper used in books, documents, archival needs, art, and the like. [0014] These and other aspects, objects and embodiments will become more apparent when read with the accompanying figures and detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 illustrates FTIR spectra of: a) untreated (control) cotton fabric; b) fabric treated with BPTCA solution (70 g/L) and cured at 160 °C; c) cured and after regular washing; and d) cured and after alkaline washing. Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C.

[0016] FIG. 2 illustrates FTIR spectra of cotton fabric treated with 70 g/L of BPTCD without washing: a) only dried at 80 °C for 5 min; b) dried at 80 °C for 5 min and cured at 160 °C for 3 minutes; and c) dried at 80 °C for 5 min and cured at 200 °C for 3 minutes. Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C.

[0017] FIG. 3 illustrates TGA and DSC of BPTCA with and without the catalyst: a) DSC of pure BPTCA; b) TGA of pure BPTCA; and c) TGA of BPTCA with catalyst (catalyst molar ratio at 0.5).

[0018] FIG . 4 illustrates TGA of pure cotton and TGA and first derivative of TGA of BPTCA treated cotton with the catalyst: a) TGA of pure cotton; b) TGA of BPTCA treated cotton with the catalyst; and c) first derivative of TGA of BPTCA treated cotton with the catalyst. Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C. [0019] FIG. 5 illustrates TGA of cotton fabrics treated with BPTCD 70g/L with and without the catalyst: a) without catalyst; b) catalyst molar ratio at 0.5; and c) catalyst molar ratio at 2. Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C.

[0020] FIG. 6 illustrates FTIR spectra of cotton treated by BPTCD after washing in 0.1M NaOH solution: a) without catalyst; b) catalyst molar ratio at 0.5; and c) catalyst molar ratio at 2. Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C. [0021] FIG. 7 illustrates FTIR spectra of: (a) a control sample; (b) the treated sample; (c) the treated sample after washing one time; (d) the treated sample after washing three times.

[0022] FIG. 8 illustrates effect of curing temperature on the add-on of BPTCA to cotton fabric.

[0023] FIG. 9 illustrates effect of BPTCA concentration on the add-on of BPTCA to cotton fabric.

[0024] FIG. 10 illustrates WRA and tensile strength retention of the cotton fabrics treated with 50 g/L BPTCD and cured at different temperature for 3 min, w: warp; f: filling.

[0025] FIG. 11 illustrates WRA and tensile strength retention of the cotton fabrics treated with different BPTCD concentrations and cured at 160 °C for 3 min.

[0026] FIG. 12 illustrates UV absorption of BPTCD in acetonitrile.

[0027] FIG. 13 illustrates SEM images of cotton fabrics: (a) control sample; (b) treated sample.

[0028] FIG. 14 illustrates TGA curves of cotton fabrics: (a) control sample; (b) treated sample

[0029] FIG. 15 illustrates impact of curing temperature on generation of ROS.

[0030] FIG. 16 illustrates amount of BPTCD on generation of ROS.

[0031] FIG. 17 illustrates repeated washing on generation of ROS.

[0032] FIG. 18 illustrates amount of BPTCD on durability of generation of ROS.

[0033] FIG. 19 illustrates curing temperature on generation of H2O2.

[0034] FIG. 20 illustrates the amount of BPTCD on the generation of H2O2.

[0035] FIG. 21 illustrates the impact of washing and lighting to H2O2 generation.

[0036] FIG. 22 illustrates the amount of BPTCD on generation of H2O2.

[0037] FIG. 23 illustrates the accelerated washing and light exposure to generation of ROS.

[0038] FIG. 24 . Amount of BPTCD on durability of generation of ROS.

[0039] FIG. 25 illustrates the effect of curing temperature on washing durability. [0040] FIG. 26 illustrates the effect of BPTCD on washing durability of generation of H₂0₂.

DETAILED DESCRIPTION OF THE INVENTION I. DEFINITIONS

[0041] The terms "a," "an," or "the" as used herein not only includes aspects with one member, but also aspects with more than one member. For example, an embodiment including "a cotton fabric material and a rayon fabric material" should be understood to present aspects with at least a second cotton fabric material, at least a second rayon fabric material, or both.

[0042] The term "aromatic" as used herein includes compounds that comprise one or more phenyl or napthyl rings. In some aspects, the phenyl or napthyl ring forms part of a larger conjugated system that can absorb ultraviolet (UV) radiation, such as the benzophenone derivatives disclosed herein. One of skill in the art can readily perceive that such structures could be varied (e.g., by addition of a halogen or Ci-C₆ alkyl substituent, such as methyl or ethyl) without changing their cross-linking or UV-absorptive (preferably, UV-protective) characteristics.

[0043] The term "about" as used herein to modify a numerical value indicates a defined range around that value. If "X" were a specified value, "about X" would generally indicate a range of values from 0.95X to 1.05X. Any reference to "about X" specifically denotes at least the values X, 0.95X, 0.96X, 0.97X, 0.98X, 0.99X, 1.0 IX, 1.02X, 1.03X, 1.04X, and 1.05X. Thus, "about X" is intended to teach and provide written description support for a claim limitation of, e.g., "0.98X." When the quantity "X" only includes whole-integer values (e.g., "X carbons"), "about X" indicates a range from (X-l) to (X+l). In this case, "about X" as used herein specifically indicates at least the values X, X-l, and X+l . When "about" is applied to the beginning of a numerical range, it applies to both ends of the range. Thus, "from about 0.2 to 2.0%" is equivalent to "from about 0.2% to about 2.0%." When "about" is applied to the first value of a set of values, it applies to all values in that set. Thus, "about 2, 4, or 7%" is equivalent to "about 2%, about 4%, or about 7%." [0044] In formulations comprising an "additional," "further," or "second" component, the second component as used herein is chemically different from the other components or first component. A "third" component is different from the other, first, and second components, and further enumerated or "additional" components are similarly different.

[0045] The term "fabric material" as used herein not only includes fabrics themselves, but also includes components used in fabrics, such as thread or yarn, as well as fibers that can be converted into fabrics or fabric components by conventional methods (e.g. , cotton before spinning; polycarbohydrate-based materials, such as rayon, that are being prepared for conversion into fabric or fabric components).

[0046] The term "polar aprotic solvent" as used herein includes solvents with a relatively high dipole moment, but no hydrogens that are exchangeable under normal conditions (e.g., no acid, alcohol, thiol, primary or secondary amine, or primary or secondary amide). Some examples of polar aprotic solvents include N,N-dimethyl formamide (DMF) and similar alkyl amides (e.g., N- methyl-2-pyrrolidinone (NMP)) as well as dimethyl sulfoxide (DMSO).

[0047] The term "or" as used herein should in general be construed non-exclusively. For example, an embodiment of "a composition comprising A or B" would typically present an aspect with a composition comprising both A and B. "Or" should, however, be construed to exclude those aspects presented that cannot be combined without contradiction (e.g., a composition that is about 5% by weight or about 10% by weight).

[0048] Generally, when a percentage range is taught, it is intended to describe all full or partial percentages in between (i.e., within the bounds of the range). For example, a percentage range of 15 to 25% would also teach inter alia the specific values of 17.36%) and 21%>. A percentage range of about 13 to 17%> would also teach inter alia the specific values of 12.97%), 16%>, and 17.1%.

[0049] "Substantially free of X" as used herein means that either no X can be detected in the mixture by conventional techniques known to the skilled artisan; or, if X can be detected, it is (1) present in <1%> w/w (preferably, <0.1%> w/w or <0.01%> w/w); and (2) does not produce the same magnitude of effects characteristic of X at higher proportions. For example, a composition substantially free of DMF would not produce the environmental effects of exposure to relatively concentrated or pure DMF even if a trace amount of DMF could be detected in the mixture that is substantively free of DMF. [0050] The term "w/w," "wt/wt," or "by weight" means a percentage calculated by taking the fraction that is the weight of the specified component over the total weight of the composition and multiplying by 100.

II. EMBODIMENTS

[0051] The frequent use and care of textile goods, such as linens, garments, fabrics, and the like, lead to the creation of wrinkles in an otherwise wrinkle-free articles. In particular, the wear and care of cellulosic-based garments such as the laundering process impart wrinkles into the garment, which require ironing, pressing and monitored tumble-drying. Frequent or difficult creasing leads quickly to consumer dissatisfaction. In addition, water-based washing many cellulosic-based textiles such as rayon leads to shrinkage of the textile goods.

[0052] The present invention provides a method for preparing a formaldehyde-free cross- linked fabric material, the method comprising: treating a fabric material comprising a polysaccharide usable for fabric with an aqueous solution of an aromatic carboxylic acid or an anhydride of the aromatic carboxylic acid; and curing the fabric material, resulting in cross-linking of the polysaccharide by the aromatic carboxylic acid or the anhydride.

[0053] The fabric thus produced is useful for wrinkle-free applications. In other instances, the fabric so produced has other following functionalities such as UV blocking and/or antimicrobial functionalities. In certain aspects, the fabric comprises photoactive compounds and structures which produce radicals under UVA or fluorescent light, which can be employed in self- decontamination applications.

[0054] In one illustrative embodiment, not intending to be limiting, an anhydride (3,3 ',4,4'- benzophenone tetracarboxylic dianhydride (BPTCD)) is dissolved in distilled water in a concentration of about 70 grams per liter (70 g/L) at elevated temperature (e.g., 70-80°C) under agitation. Thereafter, a catalyst is added such as sodium hypophosphite monohydrate or monosodium phosphate to the BPTCD solution based on a molar ratio of the catalyst versus BPTCD. The BPTCD will be hydrolyzed to 3,3 ',4,4'-benzophenone tetracarboxylic acid (BPTCA) as shown in Scheme 1. (See, Hou et al., Carbohydrate Polymers, 95, 768-772 (2013) and Hou et al., Carbohydrate Polymers, 96, 435-439 (2013)). A fabric (such as a cotton fabric) is first impregnated in the solution containing both BPTCA and the catalyst, then padded through two dips and two nips to reach an average wet pickup of 120%. Thereafter, cotton fabric is dried at 80°C for 5 min, and cured in a curing oven (Roaches International Ltd., Staffordshire,

England) at a specified temperature for 3 min. Finally the treated fabric is washed with water and air-dried in a conditioning room (25°C, 65% R.H.) for 24 hours. Optionally, the fabric can be washed with an alkaline wash to provide a durable ester bond connection.

[0055] As shown in Scheme 1 below, the cellulose becomes cross-linked.

[0056] FIG. Id shows a vibrational absorbance at 1722 cm^"1, which is a clear indication of the formation of ester bonds between the benzophenone derivative and cellulose, while the existence of free acid show overlapped band at 1722 cm^"1. The alkaline washing treatment of the fabric also proved durable ester bond connection between BPTCD and cotton cellulose. In certain instances, the methods include an aromatic carboxylic acid reacting with the fabric material comprising a polysaccharide to form an ester bond directly without formation of an anhydride to crosslink the fabric material.

[0057] According to the reactions of 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPTCD) in aqueous solution and on cellulose, 3,3',4,4'-benzophenone tetracarboxylic acid (BPTCA) is the active agent in the system. A BPTCA aqueous solution under elevated temperature is prepared and used in treatment of cotton fabrics. To further understand the overall reactions of BPTCA in water, on cellulose, and cross-linking cellulose, structure analysis of the cellulose and BPTCA was conducted and the results indicate that BPTCA brings multiple functions onto cotton fabrics in a simple one step wet finishing process. A. Treatment Solution [0058] The treatment solution for the cross-linking reaction is preferably an aqueous solution. The aromatic polycarboxylic acid or anhydride is preferably dissolved in an aqueous solution such as distilled water at elevated temperature under agitation. In certain instances, the methods are carried-out in an aqueous solution substantially- free of a polar, aprotic solvent. For example, in certain instances, the aqueous solution is substantially-free of N,N-dimethyl formamide. In other aspects, the aqueous solution has no detectible amount of a polar aprotic solvent such as no detectible amount of Ν,Ν-dimethyl formamide.

[0059] The methods of the invention comprise an aromatic carboxylic acid or an aromatic anhydride. In certain instances, the aromatic carboxylic acid is multifunctional. In certain instances, the aromatic carboxylic acid is an aromatic dicarboxylic acid or tricarboxylic acid, or tetracarboxylic acid and combinations thereof. In a preferred embodiment, the aromatic carboxylic acid is 3,3',4,4'-benzophenonetetracarboxylic acid. In certain other instances, the methods of the invention comprise an anhydride of a multifunctional carboxylic acid. Suitable aromatic polycarboxylic acids or anhydrides are shown in the Table below.

[0060] A suitable anhydride is 3,3',4,4'-benzophenone tetracarboxylic dianhydride. Other suitable carboxylic acids or anhydrides include, 1,2,4-benzenetricarboxylic acid anhydride, 4,4'- oxydiphthalic anhydride, 1,3,5-benezenetricarboxylic acid, 1,4,5,8-napthalenetetracarboxylic dianhydride, 3 ,3 ,4,4 ' -diphenyl tetracarboxylic dianhydride, 3 ,3 ' ,4,4 ' -diphenyl sulfone tetracarboxylic dianhydride, terephthalic acid and isophathalic acid.

[0061] In a typical reaction, the carboxylic acid or anhydride is present at about 20-200 g/liter of distilled water, preferably about 30-150 g/liter, and more preferably, about 40-100 g/liter of water, such as 40, 50, 60, 70, 80, 90 or about 100 g/liter. [0062] In certain preferred aspects, the methods include a catalyst to facilitate the cross-linking by the cross-linking agents with reactive sites on the polysaccharide usable for fabric (e.g., cellulose or cellulosic containing fabrics). Suitable catalysts include metal salts, mineral acids, organic acids and salts thereof. The fabric is typically treated with an amount of catalyst sufficient to catalyze cross-linking of the fibers to provide a durable press treatment.

[0063] The treating step comprises contacting the fabric material with a catalyst in

approximately 1 : 1 molar ratio with the polycarboxylic acid or an anhydride of the carboxylic acid. In other instances, the ratio of catalyst : carboxylic acid or an anhydride is 5 : 1 to 1 :5 such as 4: 1, 3: 1; 2: 1, 1 : 1, 1 :2, 1 :3, 1 :4 or 1 :5. In other instances, the catalyst : carboxylic acid ratio is about 1 : 1, 1 :0.9, 1 :0.8, 1 :0.7, 1 :0.6, 1 :0.5, 1 :04., 1 :0.3, 1 :02, and 1 :0.1.

[0064] In certain instances, the catalyst is a phosphorous salt. In certain instances, suitable catalysts include sodium hypophosphite Na₂HP0₂, sodium phosphite Na₂HP0₃, monosodium phosphate NaH₂P0₄, disodium phosphate Na₂HP0₄, trisodium phosphate Na₃HP0₄, tetrasodium pyrophosphate Na₄P₂0₇, sodium triphosphate NaP₃Oio, and sodium hexametaphosphate (NaP0₃)₆.

[0065] In certain other instances, suitable salts include hypophosphite or a phosphite salt. For example, the phosphorous salt is selected from the group consisting of sodium hypophosphite and sodium phosphite. In certain instances, the treating step comprises contacting the fabric material with a phosphate salt. In certain preferred instances, the catalyst is a phosphate salt selected from the group consisting of Na₂P0₄, and Na₂HP0₄.

[0066] In certain instances, the treating step is carried-out at a low pH. For example, the pH can be less than 7. In other instances, the pH is between 1-6 such as 1, 2, 3, 4, 5 or 6. In other instances, the pH is between 1-4, or 2-4 or 2-3. Typically, the treating step is maintained at a pH of from about 1 to about 7, and more preferably from about 1.5 to about 3.5, more preferably from about 1.5 to about 4.

[0067] Suitable fabric material comprising a polysaccharide usable for fabric includes, but is not limited to, a cotton, a rayon, a regenerated cellulose fabric, a cotton-rayon blend, or a cotton- linen blend. In other aspects, fabric comprising cellulose includes, but is not limited to, cotton, linen, flax, rayon, cellulose acetate, cellulose triacetate, hemp and ramie fibers. In other instances, fabric material includes blends of cotton with other fibers, preferably rayon and synthetic fibers. Preferred blends include for example, 50/50 cotton/rayon, 60/40 cotton/rayon, 50/50 cotton/synthetic, 65/35 cotton/synthetic, 50/50 rayon/synthetic, 60/40 cotton/synthetic, 65/35 rayon/wool, 85/15 rayon/flax, 50/50 rayon/acetate, cotton/spandex, rayon/spandex, and combinations thereof.

[0068] Suitable polysaccharides useful for fabric include, but are not limited to, a-cellulose, β- cellulose, cellulose diacetate, or a cellulose xanthate. [0069] In some embodiments, the methods comprise dipping and nipping the fabric material before the curing step. In other aspects, the methods comprise a step of drying the fabric material before the curing step.

B. Curing

[0070] In certain instances, the methods comprise curing the fabric material. This typically results in cross-linking of the polysaccharide with the aromatic carboxylic acid or the anhydride. The curing step may comprise heating. For example, the curing may comprise a temperature of between about 120 °C and 200 °C such as 120°, 130°, 140°, 150°, 160°, 170°, 180°, 190° or 200 °C.

[0071] In certain instances, the curing step comprises heating to an elevated temperature. Suitable temperature include, a temperature of between about 80 °C to about 210 °C, or about 120 °C to about 200 °C, or about 140 °C to 180 °C, or about 150 °C to about 160 °C, or about 160 °C. In certain instances, the curing step comprises heating for about 1 minute to about 1 hour, or about 1 minute to about 50 minutes, or about 1 min to about 60 minutes, or 20, 25, 30, 35, 40, 45, 50, 55 or 60 minutes. In other instances, the curing step comprises heating for about 1 to 6 minutes or 10 minutes, such as 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 minutes, such as the curing step comprises heating for about 3 minutes.

[0072] Advantageously, the curing step is substantially-free or completely-free or absolutely- free from formaldehyde or poly(formaldehyde). For example, in certain instances the curing step includes no detectible formaldehyde or poly(formaldehyde). [0073] In another embodiment, the present invention provides a fabric material product prepared by the methods described herein. The reaction mixture to provide the fabric material product is substantially- free from a polar aprotic solvent. For example, the reaction mixture comprises no detectible amount of a polar aprotic solvent, or is substantially-free from N,N- dimethyl formamide, or the reaction mixture comprises no detectible amount of N,N-dimethyl formamide.

[0074] In certain aspects, the reaction mixture is free from formaldehyde or

poly(formaldehyde). For example, the reaction mixture comprises no detectible amount of formaldehyde or poly(formaldehyde).

[0075] In another embodiment, the present invention provides a fabric material substrate for a curing reaction, wherein the fabric material substrate comprises a polysaccharide, an aromatic carboxylic acid, and water; and wherein the fabric material substrate is substantially free from Ν,Ν-dimethyl formamide, formaldehyde, or poly(formaldehyde). In a preferred aspect, the fabric material substrate comprises no detectible amount of Ν,Ν-dimethyl formamide, formaldehyde, or poly(formaldehyde).

C. Finishing

[0076] After curing at elevated temperatures, the treated fabric material can be washed in water. The finishing wash can optionally include additional ingredients to enhance the characteristics of the final finished textile. Such ingredients include, but are not limited to, wetting agents, brighteners, softening agents, stain repellant agents, color enhancing agents, anti- abrasion additives, water repellency agents, UV absorbing agents and fire retarding agents. The resulting finish on textiles treated with such finishing compositions would then contain such additional ingredients. [0077] In certain instances, the methods employ aromatic polycarboxylic acids to cross-link cellulose. The products produce result in structures of polyester in cotton. One embodiment of the a cross-linked polyester cellulose structure is shown below.

[0078] The variables n and y can be the same or different. The values of n and y can range from 200 to 15000 such as 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000,5000, 6000, 7000, 8000, 9000, 10,000, 11,000, 12,000, 13,000, 14,000 or 15,000.

[0079] The fabrics of the invention can be manufactured into garments. The wrinkle-free wearable articles comprising fabrics, including, but not limited to, shirts, blouses, dresses, pants, sweaters and coats.

[0080] The wrinkle recovery of the fabric was determined by applying American Association of Textile Chemists and Colorists (AATCC) Method 66-2008. This test method is used to determine the wrinkle recovery of woven fabrics. Briefly, a test specimen is folded and compressed under controlled conditions of time and force to create a folded wrinkle. The test specimen is then suspended in a test instrument for a controlled recovery period, after which the recovery angle is recorded. Wrinkle recovery is a property of a fabric which enables it to recover from folding deformations. Two angles are measured including warp direction and filling direction. When added together, the processes herein generate angles between at least 160° to 270° such as at least 160°, 170°, 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260° or 270°.

III. EXAMPLES

1. Experimental 2.1 Materials [0081] Desized, scoured, and bleached pure cotton plain woven fabrics (#400) were purchased from TestFabrics, Inc. (West Pittston, PA). 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPTCD) and sodium hypophosphite monohydrate were purchased from Sigma Chemical Co. (Louis, MO, USA). All other chemicals were purchased from Fisher Scientific (Pittsburgh, PA, USA). All reagents were used as received without any further purification.

2.2 Preparation of functional cotton fabrics

[0082] BPTCD was dissolved in distilled water in a concentration of 70 g per liter (70g/L) at 70-80 °C under agitation. Sodium hypophosphite monohydrate was added as a catalyst to the BPTCD solution based on a molar ratio of the catalyst versus BPTCD (Yang, C. Q., Journal of Polymer Science Part A: Polymer Chemistry, 31, 1187-1193 (2003); Yang, C. Q., and Wang, X., Textile Research Journal, 66, 595-603 (1996)). BPTCD is hydrolyzed to become BPTCA. The cotton fabric was first impregnated in the solution containing both BPTCA and the catalyst, then padded through two dips and two nips to reach an average wet pickup of 120%, dried at 80 °C for 5 min, and cured in a curing oven (Roaches International Ltd., Staffordshire, England) at a specified temperature for 3 min. And finally the treated fabrics were washed with water and air- dried in a conditioning room (25 °C, 65% R.H.) for 24 hours. Additional washing in sodium hydroxide (0.1N) was performed for FTIR analysis only.

2.3 Characterization of treated fabrics

[0083] Fourier transform infrared (FTIR) spectroscopy was performed with a Nicolet 6700 FTIR spectrometer (Thermo Electron Co., USA) with a resolution of 4 cm^"1, and measurements were carried out by using KBr pellets. Differential scanning calorimeter (DSC) and

Thermogravimetric analysis (TGA) of samples were carried out using a Shimadzu DSC-60 and TGA-60 system (Shimadzu science instruments, Inc., USA) at a heating rate of 10 °C /min from room temperature to 500 °C under a nitrogen atmosphere. 3. Results and discussion

3.1. BPTCD treatment of cotton fabrics

[0084] The anhydride groups in BPTCD are both reactive with water and hydroxyl groups in cellulose structure, and the reactions between these groups can lead to formations of carboxylic acids and ester bonds quickly (Yang, C. Q., Journal of Polymer Science Part A: Polymer Chemistry, 31, 1187-1193 (2003); Yang, C. Q., and Wang, X., Textile Research Journal, 66, 595-603 (1996)). When BPTCD is added into hot water, the anhydride is hydrolyzed to polycarboxylic acids, making the compound soluble in water. The solution was applied onto fabrics by a dip-nip-dry-cure process. Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 C. The chemical structures of the aqueous BPTCD solution treated cotton fabrics were examined by using FTIR.

[0085] FIG. 1 shows FTIR spectra of the untreated (control) cotton fabric (FIG. la), the fabric treated with the BPTCD solution (70 g/L) and cured at 160 °C (FIG. lb), cured and after regular washing (FIG. lc), and cured and after alkaline washing (FIG. Id), respectively. The formation of carbonyl bonds at 1722 cm^"1 on the cotton sample treated with BPTCA is clearly noticeable in FIG.s lb, lc, and Id. Regular washing did not remove the incorporated chemical (FIG. lc). After alkaline (0.1 M NaOH) washing, the band at 1722 cm^"1 weakened but a strong new band at 1585 cm^"1 appeared, which is corresponding to carboxylate ions (COO ), indicating that free carboxylic acids are converted to the salt of the acid. The vibrational absorbance at 1722 cm^"1 in FIG. Id is a clear signal of formation of ester bonds between the benzophenone derivative and cellulose, while the existence of free acid show overlapped band at 1722 cm^"1. The alkaline washing treatment of the fabric also proved durable ester bond connection between BPTCD and cotton cellulose. 3.2. Anhydride formation

[0086] According to the reaction mechanism of butane tetracarboxylic acid (BTCA) reaction on cellulose, the polycarboxylic acid groups will form an anhydride, and then the active anhydride will react with hydroxyl groups of cellulose to form ester bonds under a catalyst, sodium hypophosphite and an elevated temperature (Yang, C. Q., Journal of Polymer Science Part A: Polymer Chemistry, 31, 1187-1193 (2003); Yang, C. Q., and Wang, X., Textile Research Journal, 66, 595-603 (1996)). Such a mechanism was first believed to be operable in the current treatment process. Thus, 3,3',4,4'-benzophenonetetracarboxylic acid (BPTCA) on the finished cotton fabrics should return to its original anhydride structure of BPTCD, and then the anhydride group will react with hydroxyl group, during curing. The formed anhydride group should be observed in the infrared spectrum of the treated cotton. However, the FTIR of the treated fabric sample (cured at 160 °C for 3 min) did not show a clear signal of the expected anhydride group (FIG. lb). Instead, strong vibrational absorbance at around 1722 cm^"1, representing both ester and carboxylic acid groups, is shown. This result is unexpected and consequently caused questions on the reaction mechanism of BPTCA with cellulose. Thus, a series of experiments were designed and conducted on the BPTCD treated cotton fabrics to confirm the observations from FTIR analysis. Fabric samples impregnated in an aqueous solution containing 70 g/L of BPTCD (catalyst in a molar ratio of 0.5) were treated in the following steps, a) only dried at 80 °C for 5 min and no washing; b) dried at 80 °C for 5 min and cured at 160 °C for 3 minutes without washing; c) dried at 80 °C for 5 min and cured at 200 °C for 3 minutes without washing. FTIR spectra of the samples are shown in FIG. 2.

[0087] Spectrum a) in FIG. 2 confirmed that the chemical applied onto the cotton is mostly an acid or polycarboxylic acid not an anhydride since no characteristic anhydride peaks (1855 cm^"1 and 1778 cm^"1) are existing in the FTIR spectrum (FIG. 2a). After the fabric was cured at 160 °C for 3 minutes, the FTIR spectrum (FIG. 2b) did not show clear signal of anhydride peaks either. However, after cured at a higher temperature, 200 °C, for 3 minutes, the spectrum revealed quite week but noticeable anhydride peaks (FIG. 2c), meaning that anhydride groups were formed at 200 °C. Such a result is very interesting and different from the literature (Yang, C. Q., Journal of Polymer Science Part A: Polymer Chemistry, 31, 1187-1193 (2003); Yang, C. Q., and Wang, X., Textile Research Journal, 66, 595-603 (1996)), indicating that at 160 °C almost no anhydride group was formed but ester bonds between BPTCD and cellulose were indeed established. It suggested that a direct esterification process between polycarboxylic acid and cellulose occurred. FTIR results also confirmed formation of anhydride of BPTCA on the cellulose under a much higher temperature (200 °C), which could cause more negative impacts on the treated fabrics. However, the newly formed anhydride groups should be able to react with cellulose to produce ester bonds or cross-linking cellulose as well.

3.3. Catalytic effect of sodium hypophosphite

[0088] To further confirm the observation from FTIR, BPTCD was hydrolyzed in hot water again, and its acid derivative, 3,3'4„4'-benzophenone tetracarboxylic acid (BPTCA), was produced. Pure BPTCA was heated up to decomposition in both DSC and TGA apparatuses with and without the catalyst, respectively. Based on the DSC of BPTCA without the catalyst, an endothermic peak at 234 °C on DSC (FIG. 3b) appeared. Thermogram of BPTXA without the catalyst reveals a major weight loss at around 200 °C. The weight loss within this range was 9.28% (200-265 °C), equivalent to losing two water molecules from BPTCA (FIG. 3a and 3b). This is the formation process of the original anhydride compound, BPTCD. Afterward, the chemical degradation begins, resulting in another major weight loss. The addition of the catalyst did not obviously alter the formation temperature of the anhydride rings and the decomposition temperature of the compound according to the TGA (FIG. 3c). The slight loss of weight in the thermogram is caused by hydrate molecules in the catalyst. However, there is no evidence showing that the addition of the catalyst affected formation of anhydride structure of this polycarboxylic acid (BPTCA).

[0089] Then, both pure cotton and a cotton fabric sample impregnated with a solution containing 70 g/L BPTCD and a catalyst in a molar ratio of 0.5 and dried at 80 °C were subjected to similar TGA tests. TGA spectra of the fabric samples are shown in FIG. 4. The TGA of the treated cellulose shows smooth and continuous weight reduction (1.44%) in a temperature range of 100 °C to 200 °C (FIG. 4b), while the pure cotton exhibited only 0.50% weight loss in the same temperature range (FIG. 4a). First derivative of the TGA curve (FIG. 4b) did not reveal any peak (FIG. 4c), a sign of continuous dehydration reaction (loss of water) during the temperature range. Both anhydride formation and direct esterification reactions could release water, resulting in related weight loss during the heating. Since FTIR of the cotton sample cured at 160 °C only showed exclusively ester bond (1722 cm^"1) (FIG. 2b), confirming that the direct esterification reaction happened, while no anhydride rings were formed, at 160 °C in this process. Thus, we believe that basically the weight loss of the samples was the esterification reaction between BPTCA and cellulose.

[0090] To further view the function of the catalyst on the reactions on cellulose, TGA of cotton fabric samples treated by BPTCA without using the catalyst and with different amounts of the catalyst were carried out and are shown in FIG. 5. All three TGA thermograms show similar weight loss patterns without major difference. In fact, the catalyst itself may also lose water in its monohydrate crystal and cause weight loss (Brenda J. Trask-Morrell, Choi, H.M., Journal of Applied Polymer Science, 51, 769-779 (1994)). The increased amount of sodium

hypophosphite could interfere with the thermogravimetric analysis. Thus, a limited temperature range of 100-160 °C was selected since the catalyst weight loss is minimal. The weight losses of the samples in the temperature range are listed in Table 1, indicating that the addition of the catalyst indeed have accelerated the weight loss of the samples during heating, a sign of accelerated reactions.

Table 1. Weight loss of the treated fabrics

[0091] Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C. More interestingly, the increased dehydration effect was more significant at the temperature range of 100-160 °C than 160-200 °C.

3.4. Reaction mechanism

[0092] Without being bound to an particular theory, based on the above analysis, it is believed that the overall reaction mechanism for this treatment process is as set forth in Scheme 1.

Scheme 1. Proposed reaction of BPTCD with cellulose

[0093] The BPTCD is hydrolyzed to BPTCA in hot water, which is then applied onto cellulose together with the catalyst, sodium hypophosphite. Under an elevated temperature (160 °C), BPTCA could directly react with hydroxyl groups of cellulose to form ester bonds. Normal esterification reaction of acids with alcohols is slow and reversible. However, the esterification of BPTCA with cellulose could be exceptional since the treatment process has the following features: 1) relatively low pH (2-4); 2) vast majority of hydroxyl groups in cellulose to react with acid groups and 3) rapid removal of water at a curing temperature above 100 °C. The removal of water molecules breaks the balance of the reaction and drives the reaction forward. The thermograms of three samples (FIG. 5) could partially prove the proposed mechanism since without catalyst esterification also occurred. FTIR spectra of the cotton samples that were used in the TGA studies were also taken (FIG. 6). The three infrared spectra are identical, though peak intensities are different at certain level. This is another solid evidence of esterification reaction occurred between BPTCA and cellulose with or without any catalyst.

[0094] The peak intensities of ester and carboxylate groups are different from the spectra (FIG. 6). A quantitative analysis of the peak intensities was carried out, and the results are listed in Table 2.

Table 2. Relative peak intensities of infrared absorbance under different amount of catalyst

[0095] Fabrics were treated with a solution of 70 g/L of BPTCD in a wet pick up rate of 120%, dried at 80 °C.

[0096] The absorbance intensities at 2900 cm^"1 (representing vibrational band of C-H of cellulose) was employed as a base, and peak intensities at 1722 cm^"1, representing ester bonds, and 1586 cm^"1, representing carboxylate, COO^" bonds, were divided by that of the base peak. The relative intensities, ratios of the intensities in Table 2, represent the amounts of ester and carboxylate groups on the treated cellulose. Clearly, without the catalyst, sodium hypophosphite, BPTCA can be incorporated onto cellulose by directly forming ester bonds. At 160 °C, addition of the catalyst at 0.5 molar ratio to BPTCD increased the intensities of carboxylate and ester groups 78% (0.42 to 0.75) and 84% (0.19 to 0.35), respectively (Table 2). Increase of the catalyst molar ratio from 0.5 to 2 raised more ester intensity (11%, from 0.35 to 0.39) than that of carboxylate group (4%, from 0.75 to 0.78). The relative amount of carboxylate groups versus the ester groups decreased from 2.25 to 2.14, and then 2, respectively, indicating that more carboxylic groups formed ester bonds when the catalyst was increased in the system. [0097] At 200 °C, anhydride groups could form (FIG. 2c), which are more reactive with cellulose than acid groups, thus the esterification reactions should proceed through two mechanisms, one by direct esterification and another by reaction of anhydride with hydroxyl groups. As a result, the relative intensities of ester and carboxylate groups are increased in most samples, and the relative amount of carboxylate groups versus ester groups was further reduced to 1.80 from 2.14, revealing more ester bonds formed under the higher temperature. And more interestingly, the relative intensity of carboxylate groups first showed increase and then rapid decreased when the catalyst was increased to a molar ratio of 2. The reduced relative intensity of carboxylic groups was even lower than that at 160 °C with the same amount of catalyst. Since the intensity change of the ester bonds was very small, overall effects of temperature and catalyst further increased ester bond crosslinking reactions between BPTCA and cellulose.

[0098] According to the above results, the catalyst indeed promoted esterification reactions between the acid and hydroxyl groups under this treatment process. It seems more catalyst could increase more ester bonds. High temperature could lead to formation of anhydride which could increase the esterification reaction. However, one noticeable change on the high temperature treated cotton is its yellow color, possibly caused by oxidation of cellulose, making the curing temperature of 160 °C a feasible and practical selection.

Conclusion

[0099] 3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BPTCD) was hydro lyzed to its acid derivative, 3,3',4,4'-benzophenone tetracarboxylic acid, BPTCA, and the acid was able to directly react with hydroxyl groups on cotton cellulose to form ester bond cross-linkings at an elevated temperature. Direct esterification between BPTCA and cellulose was confirmed by using both thermogravimetric and infrared analyses and could be promoted by addition of a catalyst, sodium hypophosphite. More catalyst and higher curing temperature promoted esterification reaction. However, higher temperature may cause unnecessary oxidation of cotton cellulose.

4.0 Antimicrobial

[0100] Treating process: BPTCD 50 g/L, wetpick 120%, 90 °C, 3 min, 160 °C, 3 min UV radiation 60 min, antimicrobial property: 100%

[0101] Stored antimicrobial functions : completely no light exposure after initial exposure No exposure Bacterial reduction 72.78%>

UVA exposure 1 hour and no storage bacterial reduction 66.60%)

UVA exposure 1 hour and stored one day bacterial reduction 60.61%)

UVA exposure 1 hour and stored seven day, bacterial reduction 68.44%>

Antibacterial properties of BPTCA treated cotton fabrics were examined against E.coli (K12, a Gram-negative bacterium) based on a modified AATCC 100 test method.

Size: 3 x 3 cm²

Concentration of bacteria: 10⁵ cfu/mL

Volume of bacteria solution: 0.3 mL 4.1 Experimental

4.2 Materials

[0102] Desized, scoured, and bleached cotton plain weave fabrics (#400) were purchased from Test Fabrics, Inc. (West Pittston, PA). 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPTCD) and sodium hypophosphite monohydrate were purchased from Sigma Chemical Co. (Louis, MO, USA). All other chemicals were purchased from Fisher Science (Pittsburgh, PA, USA). All reagents were used as received without any further purification.

4.3 Preparation of functional cotton fabrics [0103] BPTCD should be dissolved in a medium before it can be applied onto cotton fabrics. In a previous work, it was dissolved in DMF and then the solution was used to treat cotton fabric to get photoactive antibacterial property (Hong, K. H., and Sun, G., Carbohydrate Polymers, 84, 1027-1032 (2011)). In this study, BPTCD was directly dissolved in hot water and applied in a wet finishing process on cotton fabrics.

[0104] A certain amount of BPTCD was dissolved in distilled water at 70-80 °C under agitation. Sodium hypophosphite monohydrate was added as a catalyst to the BPTCD solution in a ratio of 1 :2. The cotton fabric was first impregnated in the solution containing BPTCD and the catalyst, then padded through two dips and two nips to reach an average wet pickup of 120%, dried at 90 °C for 3 min, and cured in a curing oven (Roaches International Ltd., Staffordshire, England) at a specified temperature for 3 min. And finally the treated fabrics were washed with water and air-dried in a conditioning room (25 °C, 65 % R.H.) for 24 hours.

4.4 Characterization of treated fabrics

[0105] Add-ons of BPTCD on the treated cotton fabrics were measured by measuring weight changes of the fabrics before and after treatment. Ultraviolet protection factors (UPF) of fabrics were measured by Ultraviolet Transmittance Fabric Analyzer, UV-1000F (Labsphere Co .USA). Fourier transform infrared (FTIR) spectroscopy was performed with a Nicolet 6700 FTIR spectrometer (Thermo Electron Co., USA) with a resolution of 4 cm^"1, and measurements were carried out by using KBr pellets. [0106] Wrinkle recovery angle (WRA) and tensile strength of the cotton fabrics were measured according to AATCC Standard Test Method 66-2008 and ASTM Standard Test Method 5035-2006, respectively. Twelve specimens (six for warp and six for filling) were tested for WRA. Ten specimens (five for warp and five for filling) were employed in tensile strength tests on an Instron 5566 (Instron Worldwide Headquarters, Norwood, USA). [0107] Washing durability of the functions of the fabrics was evaluated following AATCC

Standard Test Method 61-2009 (2A). The fabric used for the washing durability tests was treated with 50 g/L BPTCD, and cured at 160 °C for 3 min. The samples were placed in a Launder-O- meter using an accelerated laundering cycle at 49 ± 2 °C in a detergent solution. Then the fabric samples were washed one, two and three times, respectively. Each accelerated washing is equivalent to five home launderings. The fabric structures (IR) and wrinkle properties (WRA) were then evaluated again.

[0108] Thermogravimetric analysis (TGA) of the fabrics was carried out using a Shimadzu TGA-50 apparatus (Shimadzu science instruments, Inc., USA) at a heating rate of 10 °C /min from room temperature to 500 °C under a nitrogen atmosphere. The surface morphologies of cotton fabrics were examined using a scanning electron microscope (Philips XL30, USA).

4.5 Results and discussion

4.6 BPTCD treatment of cotton fabrics

[0109] The anhydride groups in BPTCD are very reactive with water and hydroxyl groups in cellulose structure, and the reactions between these groups can lead to formations of acids and ester bonds quickly [Yang, C. Q., Journal of Polymer Science Part A: Polymer Chemistry, 31 , 1 187-1 193 (2003)]. When BPTCD is added in hot water, the anhydride will be hydrolyzed to acids, making the compound soluble in water. The solution was applied onto fabrics by a dip- dry-cure process. Impregnation (dip) of the fabrics in the solution and compression (nip) of the wet cotton fabrics under pressure can control the amount of chemicals homogenously deposited on the cellulose. The fabrics were then dried at 90 °C for three minutes to remove water, and cured at an elevated temperature for certain time to intrigue the reactions of formation of anhydride groups and esterification reaction. The overall reaction of this treatment process are shown in Scheme 1.

[0110] The structural changes of BPTCD treated cotton fabrics were examined by using FTIR. FIG. 7 shows FTIR spectra of the untreated (control) cotton fabric, the fabric treated with BPTCD, and the treated cotton fabrics after washing for different times. The formation of an ester bond at 1722 cm^"1 on the cotton sample treated with BPTCA 50 g/L is easily noticeable in FIG. 7. After one and three times of accelerated washing the fabrics still revealed the presence of the ester peaks, proving a successful chemical reaction between BPTCD and cotton fiber as well as the laundry durability of the treatment. [0111] The chemical reaction process of BPTCD on the fabrics was further analyzed. Fabric samples impregnated in a solution containing 70 g/L of BPTCD were examined with FTIR after going through the following steps, a) without curing, b) cured at 160 °C for 5 minutes without washing, c) cured at 160 °C for five minutes and washed, and d) cured at 160 °C for five minutes and washed in 0.1 N NaOH solution.

[0112] In this study, different concentrations of BPTCD (10, 30, 50, 70 g/L) as reactant were used to crosslink with cotton fiber at specified curing temperature (140, 160, 170, 180 °C) as reacting condition. (BPTCD is hydrolyzed to BPTCA.) The effect of curing temperature on the add-on of BPTCA to cotton fabric, with BPTCD concentration 50 g/L, is shown in FIG. 8. It shows that with curing temperature from 140 °C to 160 °C, the add-on slightly increased.

However, when the curing temperature was further increased from 160 °C to 180 °C, the add-on had not obvious change. The effect of BPTCD concentration on the add-on of BPTCA to cotton fabric, curing temperature 160 °C, is shown in FIG. 9. FIG. 9 indicates that at low

concentration, with increasing BPTCD concentration from 10 g/L to 30 g/L, the add-on increased drastically, afterwards, the add-on also increased gradually. It shows that at certain reacting condition, with increasing the amount of BPTCD, much more BPTCA reacted with cotton fibers.

4.7 Wrinkle recovery and mechanical properties

[0113] After the cellulose was grafted with BPTCA, strong and durable covalent ester bonds were formed between the hydroxyl group of cotton cellulose and the anhydride structure of

BPTCA. In order to investigate the effect of curing temperature on wrinkle recovery property, the cotton fabric was treated with 50 g/L BPTCD and cured at different temperatures ranging from 140 °C to 180 °C. During treatment, BPTCA can crosslink with cotton fiber and form ester bond, and the amount of ester increases as the curing temperature increases (Yang, C. Q. and Wei, W., Textile Research Journal, 70, 143-147 (2000)). The WRA of the control fabric sample was 154.2 degree. The effect of curing temperature on WRA of the treated cotton fabrics is shown in FIG. 10. It can be seen that the WRA increased gradually with the curing temperature increase, especially from 140 °C to 160 °C, and also shows that much more crosslinking reaction took place at higher temperature. The tensile strength retention (warp and filling) of the treated cotton fabrics is plotted against curing temperature also in FIG. 10. It demonstrates that tensile strength retention in both warp and filling directions decreased with increasing curing

temperature. Considering wrinkle recovery property and tensile strength, curing temperature at 160 °C was suitable. Even though the add-on of BPTCA to cotton fabric at higher curing temperature had not obvious improvement from FIG. 8, more crosslinking reaction took place for BPTCA with cotton fibers, and restricted the slipping between fibers.

[0114] Different BPTCD concentrations (10, 30, 50, 70 g/L) were used to treat cotton fabrics at curing temperature 160 °C for 3 min. WRA of the cotton fabrics treated with different BPTCD concentrations is shown in FIG. 11. When the BPTCD concentration was increased from 10 g/L to 50 g/L, the WRA significantly increased. However, the concentration was further increased to 70 g/L, the WRA had not obvious improvement. The tensile strength retention (warp and filling) of the treated cotton fabrics is plotted against BPTCD concentration also in Fig. 11. It is observed that the tensile strength retention gradually decreased with increasing BPTCD concentration from 10 g/L to 50 g/L. When the concentration reached 70 g/L, the further decrease of tensile strength retention was not significant. This was agreed with the WRA tendency. At definite reaction condition, i.e. at the same curing temperature 160 °C for 3 min, the amount of 50 g/L BPTCD was nearly enough to react with cotton fiber.

[0115] As functional textile material, the laundry durability is very important. The laundry durability of WRA was also investigated. WRA (w + f) for the treated cotton fabric was 236 degree, for washing one time sample being 232 degree, for washing two times sample being 233 degree, and for washing three times sample being 231 degree. These indicate that the

crosslinking between BPTCD and cotton fibers had excellent laundry durability. This is also agreed with the result of FTIR of the samples.

4.8 UV-protective properties of the materials

[0116] BPTCD, as a derivative of benzophenone, has a strong absorption of ultraviolet in 200- 400 nm regions. The UV absorption spectrum of BPTCD in acetonitrile is shown in FIG. 12. It indicates that BPTCA have three strong absorption bands in 200-250nm, 250-280 nm and 280- 325 nm.

[0117] As well known, the radiation of sunlight in the range between 100 and 400 nm is subdivided into UV-C (100-280 nm), UV-B (280-315 nm) and UV-A (315-400 nm). Due to absorption of ozone layer in the upper atmosphere, UV-C is filtered. UV radiations reaching the earth's surface are mainly UVB and UVA. In practice, Ultraviolet Protection Factor (UPF) is used for evaluating the UV protection property of fabrics. The UPF is calculated according to Eq.(l).

400

|E_A x S_A χ άλ

UPF 290

400

^E x S x T x d

2⁹⁰ (1) where Sx is erythema action spectrum, Έχ is solar irradiance, άλ is wavelength interval in nm, and Ύχ is spectral transmittance of the specimen.

[0118] Usually, UPF value of 15-24 is classified as good protection, 25-39 as very good and above 40 as excellent protection against solar UV radiation (Czajkowski, W. et al., Dyes and Pigments, 71 , 224-230 (2006)). UPF values of the cotton fabrics treated with BPTCD, 50 g/L, cured at different temperatures for 3 min, and treated with different BPTCD concentrations, cured at 160 °C for 3 min were measured. The results are summarized in Table 3.

Table 3 UV protection properties of the treated cotton fabrics and control fabric.

Curing UPF UV-protection BPTCD UPF UV-protection temperature class concentration class

(°C) (g L)

Control 4.95 Not good 0 4.95 Not good

140 52.97 Excellent 10 27.07 Very good

160 55.97 Excellent 30 55.18 Excellent

170 56.02 Excellent 50 53.42 Excellent

180 67.53 Excellent 70 54.53 Excellent [0119] It shows that the control sample had a low UPF value (4.95). The UPF values of the cotton fabrics treated with BPTCD, 50 g/L, and cured at different temperatures for 3 min, all exceeded 50, so they had excellent UV protection property. At curing temperature 160 °C, the cotton fabric treated with BPTCD, 10 g/L, had a very good UV protection property, and when BPTCD concentration was 30 g/L, or more than that, all the treated cotton fabrics had excellent UV-protective property. It can be seen that BPTCD as a derivative of benzophenone can be used to improve the fabric performance of ultraviolet resistance. The UV protection properties of the treated fabrics are mainly attributed to absorbing UV radiation by the carbonyl in benzophenone, which causes the change of the molecular structure based on internal conversion and intersystem crossing to triplet excited state. The single excited state of the carbonyl in benzophenone is easy to convert triplet excited state by intersystem crossing (Christensen, S. K., Chiappelli, M. C. and Hayward, R. C, Macromolecules, 45, 5237-5246 (2012)). The absorbing UV mechanism of the cotton fabric treated with BPTCD is shown in Scheme 2.

Excited state

Scheme 2. Absorbing UV mechanism of the treated cellulose materia

3.4. Surface morphology and thermal property

[0120] SEM analysis of the treated cotton fabric was used to characterize the changes about the surface morphology of cotton fiber. Fig. 13 (a), (b) are the SEM of the control cotton fabric and the fabric treated with 50 g/L BPTCD, cured at 160 °C for 3 min, respectively. FIG. 13 indicates that after cotton fiber was cross-linked with BPTCD at high temperature, the surface morphological structure of the cotton fiber had not obvious change. [0121] Thermal properties of the control cotton fabric and the treated cotton fabric were investigated by TGA, shown in FIG. 14. It can be seen that the thermal degradation residue of the treated cotton fabric was more than that of control cotton fabric, while the decomposition temperature of the treated fabric slightly decreased. For the treated cotton fabric with BPTCD, fibers were cross-linked, so increased the carbonization rate during the thermal degradation.

4.9 Conclusion

[0122] BPTCD was able to crosslink with the hydroxyls on cotton fiber via pad-dry-cure method, sodium hypophosphite monohydrate as catalyst, and water as medium. BPTCD, 50 g/L, was used to treat cotton fabrics, and cured at 160 °C for 3 min. Because ester bonds were formed between BPTCD and cotton fibers, the treated fabrics had excellent UV protection property and good laundry durability. U V-protection materials based on the grafted cotton also had good wrinkle recovery. The mechanical property and surface morphology had not obvious change. This imparted cotton fabric multifunctional properties. Other catalysts include phosphate salts such as Na₃PH0₄, and Na₂HP0₄. 5.0 I ROS Generation— Hydroxyl Radical

[0123] Indirect spectrophotometrical method was used to measure the generation of ROS by the cotton treated by BPTCA. The agent used for measuring hydroxyl radicals is p- nitrosodimethylaniline (p-NDA), which only reacts with hydroxyl radicals generated in the system. Treated fabrics were immersed in 20 mL p-NDA PBS solution (20 μιηοΙ/L) and irradiated under UVA light (365 nm). The concentration of p-NDA left in the solution after different exposure time was measured quantitatively through calibration method with UV-vis spectroscopy at 440 nm. FIG. 15 and Table 4 show the effect of curing temperature on free- radical formation.

Table 4 Impact of curing temperature on generation of ROS [AC (P-ND A)/C (P-NDA) (%)]

100 60.67 61.96 62.31 63.25

120 65 66.44 66.38 67.62

5.1 1-1. HO radical-curing temperature

[0124] The BPTCA treated (50g/L) cotton were dried at 90 °C for 3 minutes and then cured at an elevated temperature for 3 minutes. Then the cured fabrics were tested with the ROS measurement method. FIG. 16 and Table 5 show the results.

Table 5. Amount of BPTCD on generation of ROS [AC(P-NDA)/C(P-NDA) (%)]

5.2 1-2. BPTCD on ROS [0125] The cotton treated with varied concentrations of BPTCD were dried at 90 °C for 3 minutes and then cured at 160 °C for 3 minutes. Then the cured fabrics were tested with the ROS measurement method.

5.3 1-3. Repeated washing on ROS

[0126] The BPTCA treated (50g/L) cotton samples which were dried at 90 °C for 3 minutes and then cured at varied temperatures for 3 minutes were exposed to UVA (365nm) for 120 min. Then ROS generated by the fabrics was measured, and then the fabrics were washed three times and were exposed to UVA (365 nm) for 120 min again and retested with the ROS measurement method. The results are shown in FIG. 17 and Table 6.

Table 6. Repeated washing on generation of ROS [AC(P-NDA)/C(P-NDA) (%)]

After wash 43.76 46.41 46.42 47.09

[0127] The BPTCA treated cotton samples which were dried at 90 °C for 3 minutes and then cured at 160 °C for 3 minutes were exposed to UVA (365nm) for 120 min. Then ROS generated by the fabrics was measured, and then the fabrics were washed three times and were exposed to UVA (365nm) for 120 min again and retested with the ROS measurement method. The results are shown in FIG. 18 and Table 7.

Table 7 Amount of BPTCD on durability of generation of ROS

[AC(P-NDA)/C(P-NDA) (%)]

5.4 Generation of H₂O₂

[0128] Hydrogen peroxide generated in the system was quantified with an indirect

spectrophotometical method with UV-vis spectroscopy according to a standard operating procedure (procedure No:GSI/SOP/BS/RA/C/7). Treated fabrics (3 x 8.4 cm²) were immersed in 6 mL DI water and exposed under UVA light (365nm) for a desired time. At every time point, 3 mL of each sample solution was mixed with 3 mL of a reagent A (water solution of potassium iodide, sodium hydroxide and ammonium molybdate tetrahydrate) and 3mL of a reagent B (water solution of potassium hydrogen phthalate (KHP)). The concentration of H₂O₂ in the sample solution was measured quantitatively with a prepared calibration curve at 351 nm.

5.5 II- 1. H₂0₂-curing temperature

[0129] The BPTCD treated (50g/L ) cotton were dried at 90 °C for 3 minutes and then cured at an elevated temperature for 3 minutes. Then the cured fabrics were tested with the H₂O₂ measurement method. The results are shown in FIG. 19 and Table 8.

Table 8. Curing temperature on generation of H₂0₂ (ppm)

20 40.6585 93.4573 98.6014 120.8519

40 61.5727 99.9606 121.6057 142.8524

60 73.2573 129.7216 156.9444 178.7041

5.6 II-2. Amount of BPTCD on H₂0₂

[0130] The cotton treated with varied concentrations of BPTCD were dried at 90 °C for 3 minutes and then cured at 160 °C for 3 minutes. Then the cured fabrics were tested with the H₂0₂ measurement method. The results are shown in FIG. 20 and Table 9.

Table 9. Amount of BPTCD on the generation of H₂0₂ (ppm)

5.7 II-3. Washing and lighting to Generation of H₂0₂ [0131] The BPTCA treated (50g/L) cotton samples which were dried at 90 °C for 3 minutes and then cured at varied temperatures for 3 minutes were exposed to UVA (365 nm) for 60 min. Then H₂0₂ generated by the fabrics was measured, and then the fabrics were washed three times and were exposed to UVA (365 nm) for 60 min again and retested with the H₂0₂ measurement method. The results are shown in FIG. 21 and Table 10.

Table 10. Impact of washing and lighting to H₂0₂ generation

[0132] The BPTCA treated cotton samples which were dried at 90 °C for 3 minutes and then cured at 160 °C for 3 minutes were exposed to UVA (365 nm) for 60 min. Then H₂0₂ generated by the fabrics was measured, and then the fabrics were washed three times and were exposed to UVA (365 nm) for 60 min again and retested with the H₂0₂ measurement method. The results are shown in FIG. 22 and Table 11.

Table 11. Amount of BPTCD on generation of H₂0₂ (ppm)

5.8 III. Washing Durability of ROS Generation— HO Radical

[0133] Samples were exposed to UVA (365 nm) for 120 min and ROS generated by the fabrics was measured. The fabrics were washed following the accelerated method (AATCC Standard Test Method 61-2009 (2 A)) and dried, and were exposed to UVA (365 nm) for 120 min again and ROS generated was measured. Then the samples were rewashed, re-exposed to UVA and retested with the ROS measurement method. A total of three repeats.

Ill- 1. HO radicals under curing temperatures

[0134] The BPTCA treated (50g/L) cotton samples which were dried at 90 °C for 3 minutes and then cured at varied temperatures for 3 minutes were exposed to UVA (365 nm) for 120 min and ROS generated by the fabrics was measured. The fabrics were washed following the accelerated method and dried, and were exposed to UVA (365 nm) for 120 min again and ROS generated was measured; Then the samples were rewashed, re-exposed to UVA and retested with the ROS measurement method. A total of two repeats. The results are shown in FIG. 23 and Table 12. Table 12. Accelerated washing and light exposure to generation of ROS [AC(P-NDA)/C(P- NDA) (%)]

5.9 III-2. Amount of BPTCD on the washing durability of ROS [0135] The BPTCD in different concentrations treated cotton samples dried at 90 °C for 3 minutes and then cured at 160 °C for 3 minutes were exposed to UVA (365 nm) for 60 min and HO radical generated by the fabrics was measured. The fabrics were washed following the accelerated method and dried, and were exposed to UVA (365 nm) for 60 min again and HO radical generated was measured; Then the samples were rewashed, re-exposed to UVA and retested with the HO radical measurement method. A total of two repeats. The results are shown in FIG. 24 and Table 13.

Table 13. Amount of BPTCD on durability of generation of ROS [AC(P-NDA)/C(P-NDA) (%)]

5.10 III-3. Wash Durability of Generation of H₂0₂

[0136] Effect of Curing Temperature on washing durability of generation of H202

The BPTCD treated (50g/L) cotton samples which were dried at 90 °C for 3 minutes and then cured at varied temperatures for 3 minutes were exposed to UVA (365 nm) for 60 min and H₂0₂ generated by the fabrics was measured. The fabrics were washed following the accelerated method and dried, and were exposed to UVA (365 nm) for 60 min again and H₂0₂ generated was measured; Then the samples were rewashed, re-exposed to UVA and retested with the H₂0₂ measurement method. A total of three repeats. The results are shown in FIG. 25 and Table 14.

Table 14. Effect of curing temperature on washing durability (ppm)

5.11 III-4. Effect of BPTCD on washing durability of generation of H₂0₂ [0137] Samples treated with different concentration of BPTCD were exposed to UVA (365 nm) for 60 min and H₂0₂ generated by the fabrics was measured. The fabrics were washed following the accelerated method and dried, and were exposed to UVA (365 nm) for 60 min again and H₂0₂ generated was measured. Then the samples were rewashed, re-exposed to UVA and retested with the H₂0₂ measurement method. A total of three repeats. The results are shown in FIG. 26 and Table 15.

Table 15. Effect of BPTCD on washing durability of generation of H₂0₂ (ppm)

Example 6

[0138] 3 grams of 1 ,2,4-benzenetricarboxylic anhydride was dissolved in distilled water in a concentration of 30 g per liter (30g/L) at room temperature under agitation. Monosodium phosphate (1.07g) was added as a catalyst to the acid solution based on a molar ratio of the catalyst versus acid at 1 :0.5. A piece of cotton fabric (Testfabric #400, 5 grams) was first impregnated in the solution containing both the acid and the catalyst, then padded through two dips and two nips to reach an average wet pickup of 120%, dried at 80 °C for 5 min, and cured in a curing oven at 160 °C for 3 min. Finally the treated fabrics were washed with water and air- dried in a conditioning room (25 °C, 65% R.H.) for 24 hours. Wrinkle recovery angle (warp + Filling) of the treated cotton fabric reached 240 according to AATCC test method of 66.

Example 7

[0139] 4,4'-oxydiphthalic anhydride (2.88) grams was hydrolyzed to its acid form and was dissolved in distilled water in a concentration of 28.8 g per liter (29g/L) at 90° C under agitation.

[0140] Monosodium phosphate (0.64 g) was added as a catalyst to the acid solution based on a molar ratio of the catalyst versus acid at 1 :0.5. A piece of cotton fabric (Test Fabric #400 5 grams) was first impregnated in the solution containing both the acid and the catalyst, then padded through two dips and two nips to reach an average wet pickup of 120%, dried at 80 oC for 5 min, and cured in a curing oven at 160 °C for 3 min. And finally the treated fabrics were washed with water and air-dried in a conditioning room (25 °C, 65% R.H.) for 24 hours.

Wrinkle recovery angle (warp + filling) of the treated cotton fabric reached 257 according to AATCC test method of 66. Example 8

[0141] 1,3,5-benzenetricarboxylic acid 3.26 grams was dissolved in distilled water in a concentration of 32.6 g per liter (33 g/L) at room temperature under agitation. Sodium hypophosphite (0.82 g) was added as a catalyst to the acid solution based on a molar ratio of the catalyst versus acid at 1 :0.5. A piece of cotton fabric (Cotton Twill, 12 grams) was first impregnated in the solution containing both the acid and the catalyst, then padded through two dips and two nips to reach an average wet pickup of 120%, dried at 80 °C for 5 min, and cured in a curing oven at 160 °C for 3 min. And finally the treated fabrics were washed with water and air-dried in a conditioning room (25 °C, 65% R.H.) for 24 hours. Wrinkle recovery angle (warp + filling) of the treated cotton fabric reached 160 according to AATCC test method of 66.

Control fabric has a wrinkle angle of 127.

[0142] It is understood that the examples and embodiments described herein are for illustrative purposes only. Various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.

Claims

WHAT IS CLAIMED IS: 1. A method for preparing a cross-linked fabric material, the method comprising:

treating a fabric material comprising a polysaccharide usable for fabric with an aqueous solution of an aromatic carboxylic acid or an anhydride of the aromatic carboxylic acid; and

curing the fabric material, resulting in cross-linking of the polysaccharide by the aromatic carboxylic acid or the anhydride.

2. The method of claim 1, wherein the fabric material is a cotton, a rayon, a regenerated cellulose fabric, a cotton-rayon blend, or a cotton-linen blend.

3. The method of claim 1, wherein the polysaccharide usable for fabric is alpha-cellulose, beta-cellulose, cellulose diacetate, or a cellulose xanthate.

4. The method of claim 1, wherein the aqueous solution is substantially- free from a polar aprotic solvent.

5. The method of claim 4, wherein the aqueous solution has no detectible amount of a polar aprotic solvent.

6. The method of claim 4, wherein the aqueous solution is substantially-free from N,N-dimethyl formamide.

7. The method of claim 6, wherein the aqueous solution has no detectible N,N-dimethyl formamide.

8. The method of claim 1, wherein the aromatic carboxylic acid is a member selected from the group consisting of an aromatic dicarboxylic acid, a tricarboxylic acid, a tetracarboxylic acid, or a combination thereof.

9. The method of claim 1, wherein the aromatic carboxylic acid or anhydride is 3,3',4,4'-benzophenone tetracarboxylic dianhydride; 1,2,4-benzenetricarboxylic acid anhydride; 4,4'-oxydiphthalic anhydride; 1,3,5-benezenetricarboxylic acid; 1,4,5,8- nathalenetetracarboxylic dianhydride; 3 ,3 ,4,4 ' -diphenyl tetracarboxylic dianhydride; 3 ,3 ' ,4,4 ' - diphenyl sulfone tetracarboxylic dianhydride; terephthalic acid and isophathalic acid.

10. The method of claim 9, wherein the aromatic carboxylic acid is 3,3 ',4,4'- benzophenonetetracarboxylic acid.

11. The method of claim 8, wherein the anhydride of the aromatic

polycarboxylic acid is 3,3',4,4'-benzophenone tetracarboxylic dianhydride.

12. The method of claim 1, wherein the aromatic carboxylic acid directly reacts with the fabric material comprising a polysaccharide to form an ester bond directly without formation of an anhydride to crosslink the fabric material.

13. The method of claim 1, wherein the method further comprises a step of nipping the fabric material before the curing step.

14. The method of claim 1, wherein the method further comprises a step of drying the fabric material before the curing step.

15. The method of claim 1, wherein the treating step comprises contacting the fabric material with a member selected from the group consisting of sodium hypophosphite Na₂H₂P0₂, sodium phosphite Na₂HP0₃, monosodium phosphate NaH₂P0₄, disodium phosphate Na₂HP0₄, trisodium phosphate Na₃P0₄, tetrasodium pyrophosphate Na₄P₂0₇, sodium triphosphate NaP₃Oi₀, and sodium hexametaphosphate (NaP0₃)₆.

16. The method of claim 1, wherein the treating step comprises contacting the fabric material with a phosphorous salt selected from the group consisting of a hypophosphite or phosphate salt.

17. The method of claim 16, wherein the phosphorous salt is selected from the group consisting of sodium hypophosphite and monosodium phosphate.

18. The method of claim 1, wherein the treating step comprises contacting the fabric material with a phosphate salt.

19. The method of claim 18, wherein the a phosphate salt is a member selected from the group consisting of NaH₂P0₄, Na₃P0₄ and Na₂HP0₄.

20. The method of claim 1, wherein the curing step comprises heating.

21. The method of claim 20, wherein the curing step comprises heating at a curing temperature of between about 120 and 200 °C.

22. The method of claim 21, wherein the curing step comprises heating at a curing temperature of between about 140 and 180 °C.

23. The method of claim 22, wherein the curing step comprises heating at a curing temperature of about 160 °C.

24. The method of claim 20, 21, 22, or 23, wherein the curing step comprises heating for about 1 to 10 minutes.

25. The method of claim 24, wherein the curing step comprises heating for about 1 to 6 minutes.

26. The method of claim 25, wherein the curing step comprises heating for about 3 minutes.

27. The method of claim 1, wherein the curing step is free from formaldehyde or poly(formaldehyde).

28. The method of claim 27, wherein the curing step includes no detectible formaldehyde or poly(formaldehyde).

29. A fabric material product prepared by the method of any of the preceding claims.

30. The fabric material product of claim 29, wherein the product is substantially free from a polar aprotic solvent.

31. The fabric material product of claim 30, wherein the product comprises no detectible amount of a polar aprotic solvent.

32. The fabric material product of claim 30, wherein the product is substantially free from N,N-dimethyl formamide.

33. The fabric material product of claim 32, wherein the product comprises no detectible amount of N,N-dimethyl formamide.

34. The fabric material product of claim 29, wherein the product is free from formaldehyde or poly(formaldehyde).

35. The fabric material product of claim 34, wherein the product comprises no detectible amount of formaldehyde or poly(formaldehyde).

36. A fabric material substrate for a curing reaction, wherein the fabric material substrate comprises a polysaccharide, a carboxylic acid, and water; and wherein the fabric material substrate is substantially free from N,N-dimethyl formamide, formaldehyde, or poly(formaldehyde).

37. The fabric material substrate of claim 36, wherein the fabric material substrate comprises no detectible amount of N,N-dimethyl formamide, formaldehyde, or poly(formaldehyde).