Crystalline structure and mechanical properties of wet-spun dibutyrylchitin fibers and products of their alkaline treatment

Dibutyrylchitin was obtained during krill chitin esterification with butyric anhydride in the presence of perchloric acid. The wet spinning of a 14.5% solution in dimethylformamide created dibutyrylchitin filaments, which were treated with an alkali solution for chitin regeneration. Fiber samples with different degrees of chitin restoration were obtained, and their fine structure and mechanical properties were investigated. The restoration of the chitin structure resulted in a gradual increase in the degree of crystallinity, the density of the structured area, the tensile strength, and the average elongation at rupture and in a decrease in the diameter of the fibers. The crystallinity degree of fully regenerated chitin, the final product of alkaline hydrolysis, reached a value close to that of native chitin. (C) 2004 Wiley Periodicals, Inc.