Water-Insoluble Polyglutamic Acid Fibers

Abstract

A water-insoluble polyglutamic acid (PGA) fiber and a preparation method thereof are provided. In the preparation method, the PGA is cross-linked by a cross-linking agent and then passes through a spinning nozzle to form PGA fibers. Therefore, the highly water-absorbing PGA, which cannot be spun by conventional methods, can be spun to form PGA fibers and maintain the high water-absorption ability.

1 . Water-insoluble polyglutamic acid (PGA) fibers, which are made by:
 (a) preparing a PGA aqueous solution having an initial viscosity of no;   (b) adding a cross-linking agent to the PGA aqueous solution to perform cross-linking reaction;   (c) performing the cross-linking reaction until a spinnable viscosity is reached, wherein the spinnable viscosity is from [η 0 + 1/500(η f −η 0 ] to <η f , and the η f  is the viscosity when the PGA aqueous solution begins to climb rod; and   (d) forming PGA fibers by spinning out the cross-linked PGA solution from a spinning nozzle.   
     
     
         2 . Water-insoluble polyglutamic acid (PGA) fibers, which are made by:
 (a) preparing a PGA aqueous solution having an initial viscosity of no;   (b) adding a cross-linking agent to the PGA aqueous solution to perform cross-linking reaction;   (c) performing the cross-linking reaction until a spinnable viscosity is reached, wherein the spinnable viscosity is from [η 0 + 1/500(η f −η 0 )] to <η f , and the η f  is the viscosity when the PGA aqueous solution begins to climb rod;   (d) reducing the rate of the cross-linking reaction; and   (e) forming PGA fibers by spinning out the cross-linked PGA solution from a spinning nozzle.   
     
     
         3 . The Water-insoluble polyglutamic acid (PGA) fibers of  claim 2 , wherein the method of reducing the rate of the cross-linking reaction is decreasing the reaction temperature. 
     
     
         4 . Water-insoluble polyglutamic acid (PGA) fibers, which are made by:
 (a) preparing a PGA aqueous solution having an initial viscosity of η 0 ;   (b) adding a cross-linking agent to the PGA aqueous solution to perform cross-linking reaction;   (c) performing the cross-linking reaction until a spinnable viscosity is reached, wherein the spinnable viscosity is from [η 0 + 1/500(η f −η 0 )] to <η f , and the η f  is the viscosity when the PGA aqueous solution begins to climb rod;   (d) forming PGA fibers by spinning out the cross-linked PGA solution from a spinning nozzle;   (e) solidifying the PGA fibers by passing through a coagulant bath after the step (d); and   (f) drying the PGA fibers to perform post-cross-linking reaction.