Radiation‐grafting of acrylic acid onto ultrahigh molecular, high‐strength polyethylene fibers

Radiation-induced grafting of acrylic acid onto ultrahigh molecular weight (UHMW) high-strength polyethylene fibers to impart heat resistance and dyeability was undertaken. A preirradiation method was employed for grafting in an aqueous solution of acrylic acid containing a small amount of Mohr's salt as inhibitor. The grafting rate for UHMW high-strength polyethylene fibers is one-tenth of that for high-density polyethylene fibers currently in use, and one-hundredth, for high-density polyethylene film. It has become clear that the preirradiation dose should be as low as 1 Mrad to keep the high strength of the starting fibers. The starting UHMW high-strength polyethylene fiber begins to shrink remarkably at around 145°C, showing a maximum shrinkage of 90%, and then breaks at 154°C. When a 24% acrylic acid graft is converted to calcium salt, the grafted fiber retains the fiber form even at 300°C and gives only a maximum shrinkage of 11%. The less than 1% acrylic acid graft UHMW high-strength polyethylene fibers and their calcium salt can be dyed to a deep shade with cationic dyes, whereas the starting fibers cannot be dyed with usual dyes including the cationic dye. © 1993 John Wiley & Sons, Inc.