CHEMICAL MODIFICATION OF NATURAL POLYMER

Abstract

The present work deals with the modification of an important natural polymer, chitosan which has been extracted from natural local resources in Egypt, the waste shrimp exoskeleton. Chitosan was modified chemically by reacting the amino groups found on C2 by different techniques such as: a) chemical modification of chitosan by different types of acid chlorides, b) Grafting of CEATS onto chitosan and c) Cross linked of chitosan by different type of dialdehydes. The obtained polymers were characterized by FT-IR, Elemental analyses, TGA, X-ray diffraction, Thermal analyses and Swelling.

The two major aims of this work were to investigate the modified polymer in metal uptake and antimicrobial activity. Chitosan benzoyl thiourea derivative has been synthesized and used successfully for the removal of 6°Co and 152 154 + Eu radionuclides from aqueous solutions. Freundlich and Langmuir isotherms were applied successfully to fit the experimented data. It has been found that the chitosan thiourea derivatives are a much better fungicidal agent (about 60 times more) than the pure CS against most of the fungal strains tested. The molecular weight and the degree of deacetylation were found to have an important effect on the growth activities of the pathogens.