SE432113B - PROCEDURE FOR MANUFACTURING FIBERS WITH POROS STRUCTURE - Google Patents

Description

The porous fibers produced in this way have an effective surface area which is much larger than for previously known fibers. The fibers may contain functional groups of any chemical type, depending on the polymer used to make the fibers. The functional groups that exist can already be adapted to the intended use of the fibers or the functional groups can also be modified by subsequent chemical reactions, so that the desired reactive groups are obtained.

The mechanical properties of the fibers produced according to the invention depend on the polymer used and the conditions in the spinning. These properties can be varied within certain limits. For a given polymeric material, the conditions under which the porous fibers are produced can also be varied within wide limits. For each set of such conditions, a certain effective surface area and a certain set of mechanical properties of the fibers produced are obtained. The fibers can thus be easily adapted to the intended use. Of course, the mechanical properties of porous fibers, made according to the present invention, are not comparable to the mechanical properties required of fibers for textile use.

Fibers made according to the invention can be used for a number of different purposes. For example, since they are used as a support structure for chemical reagents, for ion exchange groups and for chelating groups, they offer a greater number of functional groups than conventional reactive fibers. The fibers of the invention can be used to make materials which can extract individual substances from mixtures containing many different components. Fibers prepared according to the invention can also be used as a support structure for the binding of soluble catalysts, especially if these are enzymes. In the latter case, "bound" catalysts are obtained, which show a very concentrated activity and a high catalytic efficiency, even on substrates with a high molecular weight.

Furthermore, fibers prepared according to the invention can be used as molecular sieves.

In the following, the invention will be further illustrated by means of some embodiments of the production and use of porous fibers according to the invention. Example 15 Preparation of porous fibers based on cellulose triacetate In a two-necked bottle with a volume of 11 and equipped with a mechanical stirrer, 50 g of cellulose triacetate (a commercial product from the company Montefibre, Pallanza) were dissolved. , Italy) in 664 g of methylene chloride. To this solution was slowly added 200 g of glycerol and the whole mass was stirred for 15 minutes at 800 rpm. The homogenized mixture thus obtained was cooled to 0 ° C and poured into a container provided with a 500-hole spinneret with a diameter of 125 μm.

The pulp was tensioned by subjecting it to a nitrogen pressure of 1 atm, and the fibers were collected on a roll after coagulation in a toluene bath at 20 ° C. The coagulation bath had a length of about 80 cm. The fibers thus obtained were dried in a dry stream of air at room temperature for 2 hours and then stored in a closed container.

The fibers had the following composition, in which: cellulose triacetate 18%, glycerol 70%, the residue i.e. 12% spinning solvent. The ratio of glycerol to polymer was 70:18 = 3.86, while this ratio was 4.00 in the ready-to-spin mixture. Virtually all of the glycerol present in the spin solution from the beginning was thus entrapped in the coagulated polymer matrix, whereby the fiber structure became porous. The fibers produced could be freed from glycerol simply by washing in water. After the fibers were completely freed of the glycerol and the spin solvents, the fibers had an apparent specific gravity of 0.253 + 0.005 g per linear meter, as measured in the manner described in Example 8.

Example 2 Preparation of porous fibers based on poly-L-gamma-methyl glutamate In a two-necked bottle with a volume of 11 and equipped with a mechanical stirrer, 290 g of PLG-30 (manufactured by Kyowa-Hakko Kogyo Co Ltd..Tokyo, Japan) were poured. which is a solution with a weight / volume concentration of poly-L-gamma-methyl glutamate with a molecular weight of 100,000-300000 in 1,2-dichloroethane (symmetrical). With slow stirring, first 145 g of 1,2-dichloroethane (symmetrical) and then 50 g of a 50% by weight solution of glycerol in water were added. The final solution thus contained: 23 g of poly-L-gamma-methylglutamate 412 g of symmetrical 1,2-dichloroethane 28 g of water II 28 g of glycerol 10 77 7722142702-3 The mixture was cooled to 0 ° C and emulsified by stirring under 30 minutes at 800 rpm, after which the mixture was poured into a container, which had previously been cooled to -6 ° C and which was provided with a 48-hole spinneret with a diameter of 80 μm. The mixture was tensioned by exposing it to a nitrogen gas pressure of 0.8 atm.

The fibers were collected on a roll after coagulation in a bath of petroleum ether maintained at 40-70 ° C. The coagulated fibers were finally cooled to -3 ° C. The resulting fibers were dried in a stream of air at room temperature for one hour and then stored in a closed container. The fibers had the following composition, by weight: 25.5% poly-L-gamma-methyl glutamate, 26.0% H 2 O; 26.0% glycerol; 22.5% spin solvent. The ratio between the dispersed phase (water and glycerol) and polymer in the fibers was thus (26 + 26): 25.5 = 2.04, while the same ratio in the spinning-ready mixture was 56:23 = 2.43. -z r i ». 1 Example gel 3 Preparation of porous fibers based on polyvinyl chloride In a two-necked bottle with a volume of 1 l and equipped with a mechanical: stirrer was poured 47.5 g_of Solvik-523 K (manufactured by Solvik, Via Filippo Turati 8, Milan, Italy), which is a copolymer of vinyl chloride and vinyl acetate containing 12% by weight of vinyl acetate, together with 452.5 g of methylene chloride. This mixture was stirred until the copolymer was completely dissolved, after which 95 g of glycerol was slowly added with stirring. The mixture was cooled to 10 ° C and emulsified by stirring for 15 minutes at 800 rpm. The mass thus obtained was poured into a container maintained at 10 DEG C. and provided with a spinning nozzle having 100 holes with a diameter of 80 .mu.m.

The spinning was performed using a pressure of 0.6 atm and the fibers were collected on a roll after coagulation in a bath of n-hexane, which was kept at 20 ° C. The fibers thus obtained were dried in a dry stream of air for two hours and stored in a closed container.

The fibers had the following composition, by weight: 29.5% copolymer Solvik-523 K; 57.9% glycerol; 12.6% spin solvent. Also in this case, each gram of coagulated polymer matrix had retained 1.96 g of glycerol, which was finely divided in the polymer matrix so that it was porous. Example 15 Use of porous fibers of cellulose triacetate as a substrate for chemical immobilization of proteins The following three types of fibers were examined: A) A porous fiber obtained by using the method described in Example 1 Spread 50 g of cellulose triacetate dissolved in 664 g of methylene chloride and 200 g of glycerol as the dispersed phase into 500 monofilament yarns, each with 3.7 denier.

B) A porous fiber prepared in the same way as the fiber according to A) but using 100 g of glycerol as the dispersed phase. Also in this case, 500 monofilaments were each made with 3.7 denier.

C) A non-porous fiber prepared in the same way as the fiber according to A) and B) but without the use of any dispersed phase. Also in this case, 500 monofilament yarns each of 3.9 denier were produced.

The above denier values are averages obtained from 10 readings made as follows: A sample of 500 monofilaments with a length of 100 cm was subjected to Sitt washing in distilled water, using for each wash 50 ml of water and a contact time of 10 min. The washing was carried out with stirring at room temperature. After washing, the sample was dried in an oven at 70 ° C and a pressure of 0.1 mm Hg for 8 hours, after which the sample was weighed.

From the dry weight thus obtained for the whole sample, the denier value of each individual monofilament was determined by multiplying the “obtained dry weight in grams by 9000: 500.

From each fiber a sample was taken in such a way that it contained an equal amount, ie. 1.78 g, cellulose triacetate, and thus exactly 9.89 g of fiber A), 5.78 g of fiber B) and 1.85 g of fiber C) were taken. Each sample was placed in a 300 ml Erlenmeyer flask and washed five times with distilled water, each time with 200 ml of water, and then treated for four hours with slow stirring and at room temperature with 200 ml of a 0.5 M aqueous solution of sodium hydroxide. This treatment converts the original polymer to cellulose and is such that it at least partially retains the original structure of the fiber, as can be seen from the results described below. After the hydrolysis, each sample was washed with water until neutral, and treated at room temperature with slow stirring and for 20 hours with 165 ml of an aqueous solution of 0.05 M phosphate buffer, pH = 8.0, containing 0.285 g of benzoquinone ( this treatment activates the fiber and makes it suitable for chemically binding protein according to the method 10 15 20 25 30 35 77í41u2-s 6 described in the Swedish patent application 7604136-7).

After this treatment, each fiber sample was washed alternately with water and with a 0.05 M phosphate buffer at pH = 8.0, until wash water no longer contained any substance with an absorbance at 250 nm. Thereafter, the fiber samples were subjected to a trypsin binding test. Each fiber sample was contacted with 47 ml of a 0.05 M phosphate buffer, pH = 8.0, which was cooled to 2 ° C and contained 47 mg of trypsin with a specific activity of 30 BAEE units per mg (an enzymatic BAEE unit is the amount of enzyme which hydrolyses one pmol per minute of N-alpha-benzoyl-L-arginine methyl ester at a pH of 8.0 and at a temperature of 25 ° C). The reaction was carried out for 24 hours with slow stirring and at 2 ° C. After completion of the reaction, the three fiber samples were washed alternately with water and with a 0.05 M phosphate buffer, pH = 8.0, until no enzyme activity could be detected in the wash. After completion of the protein binding reaction, the remaining enzyme activity of the reaction solution was matted. It was: 7§9 BAEE units / ml Solution in contact with fiber samples 13): 13,1 - ".- 25,2 -" - When measuring the enzyme activity bound to the fiber samples Solution in contact with fiber samples A): Solution in contact with fiber sample C): the following values were obtained: Fiber A) 650 BAEE units per gram of dry product Fiber B) 450 - "- ^ _h 'Fiber C) 80 -" - Example 5 - ~ ¿Use of porous fibers based on cellulose triacetate as a substrate for chemical immobilization of proteins 494 g of the fiber A) according to Example 4 were washed with water, then hydrolyzed with 100 ml of 0.5 M NaOH and then subjected to an activation reaction with 83 ml of 0.05 M phosphate buffer, pH = 8.0, containing 0.142 g of benzoquinone. Then the fiber was washed.

This procedure is identical to that used in Example 4. The fiber sample thus obtained was reacted with the enzyme penicillin acylase under the following conditions. The sample was contacted with slow stirring for 24 hours at room temperature with 25 ml of a 0.04 M phosphate buffer, pH = 7.6, containing 38 units / ml of penicillin acylase from Escherichia Coli (ATCC-9637) with a specific activity _ _ __ _ allows l nmol / min of 5 units per .ng protein. An enzymatic unit is the amount of enzyme converted to penicillin G to 6-aminopenicillanic acid and phenylacetic acid under the following conditions: temperature 37 ° C, pH = 8.0, phosphate buffer 0.01! And penicillin G = 2% by weight, total volume 200 ml and a total of 15-30 enzyme units present, under these conditions the measure of the initial rate of the enzymatic reaction, as expressed in μmol per minute, corresponds to the enzyme units After the sample was washed to remove unreacted enzyme in the manner described in Example 4, the enzymatic activity remaining bound to the fiber sample was determined. This activity was 444 μmol per minute and per gram of dry product.

Example 6 Use of porous fibers of poly-L-gammaethyl glutamate as a substrate for chemical immobilization of proteins 3.92 g of the fiber of poly-L-gamma methyl glutamate prepared according to Example 2 were washed with 50 ml of distilled water 4 times to remove glycerol and then 5 times with absolute methanol 50 ml each time, to remove water, and finally slurried in 50 ml of absolute methanol containing 2.0 mmol of hydrazine hydrate.

The mixture was kept under slow stirring at room temperature. The reaction was monitored by titrating the loss of hydrazine from the reaction solution. After 0.98 mmol of hydrazine had disappeared from the solution, the reaction was stopped by filtering off the fibrous substrate from the methanol solution and washing 3 times with 50 ml of methanol.

The fibrous substrate was then washed with cold water (1-2 ° C) and then immersed in 100 ml of 0.5 M aqueous solution of HG1, which was kept on an ice bath. To this mixture, which was kept under stirring, was added in small steps over 15 minutes 1 g of sodium nitrite. After this addition, the mass was kept under stirring in the cold state for one hour, after which the fibrous substrate was washed with a cold 0.01 M aqueous solution of HCl. Finally, the fiber was soaked in 100 ml of 0.1 M phosphate buffer, pH = 8.5, containing 100 mg of trypsin with a specific activity of 30 BAEE units / mg. The mass was stirred overnight at 0 ° C. The fibrous substrate was washed with water until no more enzyme activity could be detected in the water, after which the enzyme activity bound to the fiber was measured. It amounted to 350 BAEE units per gram of dry product. Example 7 Use of porous fibers of polyvinyl chloride as a substrate for chemical immobilization of proteins 3.39 g of the fiber prepared according to Example 3 were washed 4 times with water, each time 50 ml water, and then 5 times with absolute methanol, 50 ml of methanol each time, and finally immersed in 100 ml of absolute methanol containing 1 ml of concentrated sulfuric acid for 6 hours. The fiber was then collected on a filter and washed with 50 ml of toluene. The fiber thus treated was immersed in a solution twice with 50 ml of methanol and 4 times of 5 g of phosgene in 100 ml of toluene at room temperature and kept under stirring overnight. Thereafter, the excess phosgene was removed by washing with toluene (5 times with 50 ml), after which the fiber was dried at room temperature in a dry stream of nitrogen. The fiber was then immersed in 100 ml of a 0.1 M phosphate buffer, pH = 7.5, cooled to 0 ° C and containing 100 mg of trypsin with a specific activity of 30 BAEE units / mg. The mass was kept under stirring in a cold state for 20 hours. Finally, unreacted enzyme was removed by washing water until no enzyme activity could be detected in the wash water.

The fibrous material thus obtained showed an enzyme activity of 250 BAEE units per gram of dry product. Example 8 Use of porous cellulose triacetate fibers as molecular sieve 137 g of cellulose triacetate fiber prepared in the manner described in Example 1 and containing 24.6 g of polymer were cut into staple fibers 0.3-0.6 cm in length and packed in a column with a diameter of 2.5 cm up to a level of 34.7 cm, so that the fiber took up a total volume of l70 ml in the bed. The fiber so packed was freed from air bubbles and washed simultaneously by eluting it with about 5 liters of water, which had previously been degassed under vacuum. The column thus obtained was found to have the properties of a molecular sieve. When subjected to gel filtration measurements using an aqueous solution of KCl (13.3 g / l) as eluent, Blue Dextran 2000 (a product of Pharmacia-Fine Chemicals AB, Uppsala, Sweden) having a molecular weight of 2 was obtained. 000,000 an elution volume of 73 ml. This value was constant in a flow range from 5 ml / h to 50 ml / h. In contrast, the elution volume of potassium bichromate having a molecular weight of 294 varied between 128 ml at 7.5 ml / h and 18 ml at 45 ml / h. These data show that the fiber acts as a molecular sieve. At the same time a method is obtained for determining the apparent density of the fiber: 170 ml (total bed volume) - 73 ml (empty volume in the column) = 97 ml. Thus, 24.6 g of polymer occupied a volume of 97 ml, so that 24.6: 97 = 0.253 g / ml.

All fiber in the column was then converted to cellulose by treatment with a 0.5 M aqueous solution of sodium hydroxide at room temperature for 8 hours, after which the fiber was packed in the same column as before and subjected to the same gel filtration measurements. The results were: Total bed volume = 100 ml Elution volume for Blue-Dextran 2000 = 38 ml Elution volume for potassium bichromate = 92 ml In this case, the elution volume for potassium bichromate was again constant within the same flow range.

Finally, the dry weight of the fiber was determined by drying the fiber at 80 ° C under vacuum. The dry weight was 14.1 g. The apparent density of the resulting cellulosic fiber was thus 4.11: (100-38) = 0.227 g / ml. IN

Claims (1)

A process for producing fibers with a porous structure by dissolving a polymer, mixing the resulting polymer solution with glycerol, spinning the mixture thus obtained and removing the dispersed phase, characterized in: I: thereof. , that the polymer used is polymeric cellulose triacetate, poly-L-gamma-methyl glutamate or a copolymer of vinyl chloride and vinyl acetate.