Patent ID: 8263763

Claim:
A chemically modified polyaminosaccharide comprising a polyaminosaccharide and sulfur, the chemically modified polyaminosaccharide capable of suppressing the depletion of the sulfur content to no more than 3% by weight upon being subjected to the treatment of an alkaline solution, said chemically modified polysaccharide being produced by a process of alkylsulfonating an un-modified polyaminosaccharide having amino functional groups by a hydrocarbyl sultone compound in the presence of an organic solvent under a reflux temperature of the organic solvent, wherein the hydrocarbyl sultone compound has a formula of: in which R 1 is selected from —(CH 2 ) x — where x is an integer of 2 to 4 and —CH═CH—; and R 2 is selected from H and a C 1 -C 3 alkyl group; and wherein the organic solvent has less than 10% water and is selected from the group consisting of methanol, ethanol, isopropanol, butanol methoxypropanol, and combinations thereof; such that a predetermined proportion of the amino functional groups in the thus-produced chemically modified polyaminosaccharide is alkylsulfonated by the hydrocarbyl sultone compound via a covalent bond.