WO2017076374A1

WO2017076374A1 - Polymer-made fibre preparation method

Info

Publication number: WO2017076374A1
Application number: PCT/CZ2016/000116
Authority: WO
Inventors: Ivana MÁROVÁ; Vojtěch KUNDRÁT; Jiří POSPIŠIL
Original assignee: Vysoké Učení Technické V Brně
Priority date: 2015-11-06
Filing date: 2016-10-24
Publication date: 2017-05-11
Also published as: CZ2015790A3; CZ306448B6

Abstract

The invention relates to the method of the polymer fibre preparation from polyhydroxybutyrate (PHB) or hydroxybutyrate - hydroxyvalerate copolymer (PHVB) by fibre spinning technology using the wet spinning, from a solution of the polymer in a solvent extruded to a precipitant, where the polymer or the copolymer concentration in solvents or the mixture of solvents is 0.1 - 20 % w/w. Using the method of the invention, the polymer fibre having submicron structure containing nanopores and micropores in the whole cross section being of diameter 200 nm - 1 μm is prepared.

Description

POLYMER-MADE FIBRE PREPARATION METHOD

Field of the invention

The invention relates to polymers containing oxygen heteroatoms in the main polymer chain and belonging into the group of the polyesters and as well as preparation method of fibres having a submicron structure by the wet spinning method from the solution of these polymers.

State of the art

Polyesters, principally polyethyleneterepthalate (PETP), are polymers, which use for production of fibres is well known many decades already. PETP is the most widespread polymers employed for the fibre production now. PETP, as well as polyamides (PA), are spinning from the melt only now.

A sustain effort is made during last 25 years to exploit in practise the other types of polyesters as well, mainly those, which can be classified as manmade polymers or made by other living organisms from the renewable sources. This can be achieved in the case of PETP only partly now, so that ethylene glycol used in the synthesis of PETP is made using the procedure based on substances belongings to the group of saccharides (carbohydrates). The examples are sucrose and starch.

Polyesters, which can be classified as manmade polymers or of made by other living organisms from the renewable sources, belongs usually to the category of biodegradable materials. There are also some biodegradable materials in this group, which are based on polymers produced from non-renewable sources, e.g. polycaprolactone (PCL).

The polylactic acid (PLA) is currently, from the quantity produced point of view, the most widespread polymer manmade or made by other living organisms from the renewable sources. Polyhydroxybutyrates are getting more and more importance now. Its production by biotechnology is described e.g. in the inventions CZ 304 183 and patent application WO 2014/032633/A1. Both PLA and PHB have the characteristic, that they must be modified to get the properties suitable for the production of the articles useful in practice and made by the melt processing (extrusion, injection moulding etc.). Actually the problem is the extremely rapid crystallization from the melt and the brittleness of the articles produced so.

The monograph [1] is dedicated to the synthesis and processing of PLA. The spinning of polymers is possible to do using three technologies: from the melt, from the wet and from the gel. The wet spinningis the well known technology and used by industry for more than 100 years already. The spinning from the melt is dominating now, about 50 - 100 million tons of fibres/monofil are made per annum now.

The spinning from the gel is employed for spinning of polyvinylchloride (PVC) and polyethylene (PE). These fibres are minor from the annual production point of view. Only approximately. 100 000 tons per annum are produced so now.

The basic information dealing with the wet spinning, some pictures including, is presented in the literature [1], [2]. The wet spinning has been and is used up to now for spinning viscose and derivatives of cellulose. It is employed further for wet spinning of polyacrylonitrile (PAN). Approx. one million tons per annum is produced using this technology at present. Many patents are dedicated to wet spinning, e.g. CN103526371, US2013300013, JP2011256488, US5234651 , US3996321, US3676540, JP2004277898, JP2004218169, JPH01156507, JPH02139407, JPS62141115, JPH0544104, JPS5988930, JPH0226911 , JPS584833 and CH707560.

The principle of wet spinning is a simple one. The polymer is dissolved and precipitated in a shape of a fibre then. It is necessary to solve the choice of both solvent or mixture of solvents and a polymer solution concentration and a polymer solution temperature. It is necessary to solve the choice of both precipitating bath or mixture of precipitants and a precipitating bath temperature. It is necessary to solve the set of the machine parameters, e.g. solution output (ml/min), spinneret holes diameter (mm), spinning speed (cm/min) and influence of the other factors [1]. If one likes to produce fibres from the polymers like polylactic acid (PLA), polycaproiactone (PCL) or polyhydroxybutyrate (PHB) are, the use of the wet spinning technology is an advantage. The solutions are also possible to be spun to nanofibres using electrospinning, as it is specified in the patents WO2014127099, US2014106167, CN103451753, DE102012004227, CN101429685, US5234651 , US3996321 ), and also to microfibers using the technology above described.

This procedure is especially advantageous in the case of PHB, because PHB is separated from a mixture obtained by biotechnology using dissolving PHB, subsequent centrifuging of a non-dissolved rest, precipitating and drying of the polymer. The pelletizing can be a subsequent step. Use of the PHB solution for the fibre production can result in the leaving out the steps of precipitating and drying. The PHB solution is possible to be wet spun to both nanofibres using electrospinning and do microfibers and also to microfibers using the technology above described. Both such spinning technologies (techniques) can be employed also for both PLA and PHB. The PHB spinning and/or copolymers PHVB (polyhydroxyvalerate-co-butyrate) is specified in the patents e.g. CN102493021 , CN102181960, CN102146598, CN102146597 a CN10293676.

It is stated for wet spinning in a literature [5], that the polymer concentrations of 15 - 60 % w/w are employed for the wet to dry spinning (solution to air (gas)) and the polymer concentrations of 5 - 25 % w/w are employed for the wet to wet spinning (solution to precipitant).

References:

1. Auras R., Loong-Tak- L, Selke S.E.M., Hideto T. (Editors): POLY(LACTIC ACID), Synthesis, Structure, Properties and Applications, J. WILEY & SONS, Inc. Publications, New Jersey 2008, ISBN 978-0-470-29366-9 (cloth)

2. Kebl F.: Technologie chemickych vlaken, SNTL Praha 1977, pages 201 and 203

3. Pachekoski, W.M., Dalmolin, C, Marcondes Agnelli, J.A. Materials Research- Ibero-American Journal of Materials 2013, 16, 2, 327-332

4. Mishra S.P.: A Text Book of Fibre Science and Technology, New Age International, Bombay 2000, ISBN 81-224-1250-5 5. Kudlacek L, Blazek J., Laurusky V.: Technologie chemickych vlaken, SNTL Praha, 1986, page 276

Summary of the invention

It was revealed, that using the poly hydroxybuty rate (PHB) concentrations from very low (0.1 % w/w) to high maximal one of 20 % w/w, at laboratory temperature 23 ° C for wet spinning (solution to precipitant) using the pure precipitant only, the resulting microfiber has not the compact cross section, but is containing nanopores and micropores in the whole cross section being of diameter 200 nm - 1 μηι.

This invention relates to the method of the polymer fibre preparation from polyhydroxybutyrate (PHB) or hydroxybutyrate - hydroxyvalerate copolymer (PHVB) by fibre spinning technology using the wet spinning, from a solution of the polymer in a solvent extruded to a precipitant, where in case of hydroxybutyrate - hydroxyvalerate copolymere the hydroxyvalerate concentration in the polymer is maximal one of 30 % w/w related to the whole co-polymer. The polymer or copolymer is having the mass average molar mass of 50000 - 1000000 Da, the precipitants are alcohols having freezing (melting) point higher than -70 °C and having the concentration at least 75 % w/w. The precipitants of the polymer or the copolymer ethanol, izopropanol a/nebo metanol. Solvents of the polymer or the copolymer are chloroform, dichlorethane and/or dichlormethane; wherein the polymer or the copolymer concentration in solvents or the mixture of solvents is 0.1 - 20 % w/w . The temperature of polyhydroxybutyrate or hydroxybutyrate - hydroxyvalerate copolymer solution is in the range of 0 °C - 50 °C and the precipitant temperature is in the range of - 70 °C - 70 °C.

The difference between densities of solvents (higher density) and the precipitants (lower density) is employed also; thereby the fibre is drawn spontaneously by gravity force also, without mechanical drawing.

From above mentioned polymers is prepared the polymer fibre using the method of the invention having submicron structure containing nanopores and micropores in the whole cross section being of diameter 200 nm - 1 μιη. Description of drawings

Figure 1 : Process chart of the wet spinning (solution to precipitant) [1]

Figure 2: Process chart of the wet to dry spinning (solution to air (gas)) to the chamber having exhausting of vapours and set temperature [1]

Figure 3: Process chart of the wet spinning with first step the wet to dry spinning (solution to air (gas)) [1]

Figure 4: The cross-sections of the viscose fibres [2]

1 - normal (classical) fibre type

2 - fibre type of higrer tenacity at wet conditions

Figure 5: Process chart of the viscose spinning [2]

1. Spinning hole surface; 2.Viscose; 3. Cellulose xanthate; 4.Regenerated cellulose

Figure 6: SEM picture of the PHB fibre with the sub-micron structure done according to the Example 1 - the whole fibre

Figure 7: SEM picture of the PHB fibre with the sub-micron structure done according to the Example 1 - the fibre sub-micron structure - detail inside the fibre

Figure 8: SEM picture of the PHB fibre with the sub-micron structure done according to the Example 1 - the fibre sub-micron structure - detail of the fibre surface

Figure 9: SEM picture of the PHB fibre with the sub-micron structure done according to the Example 7 - the whole fibre

The invention is illustrated by the following Examples in a non limiting way, not limiting the other performances being in the range of this patent application claims. Examples

Example 1

Polyhydroxybutyrate (PHB) spinning

The polymer fibre was prepared from commercially available polyhydroxybutyrate (PHB) having the mass average molar mass of 900 000 Da. The solution of the polyhydroxybutyrate (PHB) in chloroform (2.5 % w/w) was prepared having the temperature 23 °C as a solvent. It was spun to the precipitant from the die of 0.3 mm diameter to ethanol (azeotropic mixture ethanol-water, containing 95.57 % w/w of ethanol) of temperature 23 °C. The volume spinning speed was 1 ml/minute and the solution speed at the spinning hole was 14 m/minute. The polyhydroxybutyrate (PHB) was precipitated in the shape of fibre at distance of approx. 30 mm from the hole end. The precipitated fibres were further dried at temperature of 23 °c and subsequently tested.

It was determined by differential scanning calorimetry (DSC), that the crystallinity of the polyhydroxybutyrate (PHB) is 60 % w/w. The crystallinity (% w/w) is (A_Sampie ioo)*100), A_sampie is the fusion enthalpy of the measured fibre sample. The fusion enthalpy of the fully crystalline PHB was taken from the literature [3] as 146 J.g^"1. Value taken for A_sampie by DSC experiment was 87.6 J.g^"1.

The fibre's submicrone structure in the whole cross-section and on the surface respectively is shown on the figures 6-8.

Example 2

Polyhydroxybutyrate spinning

The example 1 was repeated but ethanol (azeotropic mixture ethanol-water, containing 95.57 % w/w of ethanol) of temperature -70 °C was employed. Example 3

Polyhydroxybutyrate spinning

The example 1 was repeated but isopropanol of temperature 23 °C as precipitant was employed.

Example 4

Polyhydroxybutyrate spinning

The example 1 was repeated but polyhydroxybutyrate (PHB) of the mass average molar mass 80 000 Da was employed.

Example 5

Polyhydroxybutyrate spinning

The example 1 was repeated but polyhydroxybutyrate (PHB) concentration 0,1 % w/w in chloroform was employed.

Example 6

Polyhydroxybutyrate spinning

The example 1 was repeated but dichlorethan as the solvent was employed.

Example 7

Polyhydroxybutyrate spinning

The example 1 was repeated but the polyhydroxybutyrate (PHB) solution was chilled to the temperature 0 °C (Fig.9). Example 8

Polyhydroxybutyrate spinning

The example 1 was repeated but the polyhydroxybutyrate (PHB) solution was heated to the temperature 50 °C.

Example 9

Polyhydroxybutyrate spinning

The example 1 was repeated but the polyhydroxybutyrate (PHB) of the mass average molar mass 80 000 Da and concentration 20 % w/w was employed. Dichlormethan as the solvent was employed.

Example 10

Polyhydroxybutyrate spinning

The example 1 was repeated but the mixture of ethanol (75 % w/w) and chloroform (25 % w/w) as the precipitant was employed.

Example 11

Polyhydroxybutyrate spinning

The example 1 was repeated but methanol as the precipitant was employed.

Example 12

Hydroxybutyrate - hydroxyvalerate copolymer (PHVB) spinning

The example 1 was repeated but hydroxybutyrate - hydroxyvalerate copolymer PHVB was employed as the polymer and hydroxyvalerate concentration in hydroxybutyrate - hydroxy valerate copolymer of 30 % w/w and of the mass average molar mass 900 000 Da was employed (see figure 15).

Industrial applicability

The polymer fibres prepared by the method of the invention are made of the renewable sources and are biodegradable. They are suitable for a liquid and gas filtrations and have utilization in the tissue engineering also.

Claims

C L A I M S

1. The method for preparation of polymer fibres made of polyhydroxybutyrate or hydroxybutyrate - hydroxyvalerate copolymer by fibre spinning from a solution of the polymer in a solvent extruded to a precipitant characterised by that, the maximal concentration of hydroxyvalerate in the hydroxybutyrate - hydroxyvalerate copolymer is 30 % w/w, wherein the polymer or the copolymer is having the mass average molar mass 50 000 - 1 000 000 Da, the precipitants are alcohols having the freezing point higher then - 70 °C and their concentration is at least 75 % w/w , the solvents of the polymer or the copolymer are chloroform, dichlorethan and/or dichlormethan, wherein the polymer or the copolymer concentration in the solvent or in the mixture of the solvents is in the range of 0.1 - 20 % w/w, the temperature of polyhydroxybutyrate or hydroxybutyrate - hydroxyvalerate copolymer solution is in the range of 0 °C - 50 °C and the precipitant temperature is in the range of -70°C - 70 °C.

2. The method for preparation of polymer fibres according to claim 1 , characterised by that, the precipitants are ethanol, isopropanol and/or methanol or mixtures thereof.