Abstract
Preparation of N-chlorinated bacterial cellulose (BC) and its ultra-thin sheet-making were investigated. N-chlorinated BC was prepared by a three step reaction: cyanoethylation, carbamoylethylation and N-chlorination. Cyanoethylated BC of DS (degree of substitution) 0.05 was prepared Michael addition with acrylonitrile at 40°C for about 2.5 h. Carbamoylethylation of cyanoethylated BC readily proceeded by addition of H2O2 at room temperature (20°C) and reached DS 0.05 for about 1 h. In the third step, carbamoylethyleted BC easily reacted with NaClO and gave N-chlorinated BC. The dry tensile index of N-chlorinated BC sheet (10 µm thickness) was about 1.7 times higher than that of a BC sheet, and the wet tensile index was about 3.6 times higher. By N-chlorination of BC, we could prepare sheets down to a thickness of 3 µm. Increasing inter-fiber bond formation of N-chlorinated BC is the reason for improving the sheet-formation.
