Abstract: Disclosed are acidic or basic gas absorptive fiber having both a degree of acidic gas absorption of 70% or higher and a degree of basic gas absorption of 80% or higher, and also fabric comprising the fiber. The fiber and fabric, after having absorbed acidic and basic gases, can easily be restored to its original condition if they are exposed to clean air. The fiber is preferably crosslinked acrylic fiber, which has a specific increase in its nitrogen content resulting from crosslinking with hydrazine, a specific amount of carboxyl groups resulting from modification with nitrile groups, a specific ratio of free carboxyl groups to all carboxyl groups existing therein, and a specific equilibrated pH in water, and which is prepared from acrylic fiber through crosslinking with hydrazine, hydrolysis, and conversion of carboxyl groups therein into metal carboxylate groups. The fiber and fabric are durable to cycle use.

Abstract: Novel porous water-absorbing acrylic fibers composed of not less than 90 weight % of an acrylonitrile polymer and having dispersed therein less than 10 weight % of a water-absorbing resin particles containing carboxyl groups (represented by --COOX wherein X is H, HN.sub.4 or an alkali-metal) and having a degree of water-swellability of 10-300 cc/g, the particle diameter of which resin is not larger than 0.5.mu. at absolute dryness, the carboxyl groups in the water absorbing resin present at least in the outer layer of the fibers being of the type where X is H, and in the inner portion being of the type where X is NH.sub.4 or an alkali metal, said fibers containing pores not smaller than 0.2.mu. in their largest diameter in the inner layer of the fibers and said fibers having a water holding ratio not lower than 20%. The acrylic fibers provided are novel, porous and water-absorbing, having a stable water-absorbing ability which will not be easily lowered by heat treatment, etc.

Abstract: Acrylic fibers consisting of not more than 90 weight % of an acrylonitrile polymer and less than 10 weight % of a water-absorbing resin having a particular cross-linking density, particle diameter and degree of water-swellability, which are excellent in practical properties such as strength, elongation, color fastness, spinnability and water-absorption.