Chitosans from Euphausia superba. 1: Solution properties

Abstract

A technological development of chitosan (copolymer of N-acetylglucosamine and glucosamine) is based on the knowledge of parameters such as composition. types of sequence, chain length and distribution. In addition to the sample source, these factors are related to preparation and purification methods. In this connection the authors examined chitosan samples having the same origin (Euphausia superba), but different degrees of acetylation, as well as materials which were subjected to regeneration and beating processes. In addition, the authors prepared chitosan samples of different degrees of polymerization by hydrolysis of commercial chitosan of high degree of acetylation under different pH and temperature conditions. The samples were characterized in 0·1n CH₃COOH (HAc) - 0·2m NaCl by intrinsic viscosity ([η]) and light scattering techniques. The viscometric behaviour of the starting chitosans and of all depolymerization products follows an expected pattern. On the other hand, light scattering shows important differences among samples having identical [η], but obtained under different hydrolysis conditions. A tentative explanation is suggested for the discrepant responses.