Fabrication and characterisation of chitosan nanoparticles/plasticised-starch composites

Chitosan nanoparticles (CNs), obtained by physical crosslinking between tripolyphosphate and protonised chitosan, were used as filler in a glycerol plasticised-starch (GPS) matrix to be used in food packaging. In GPS/CN composites, the chemical structures of the matrix and the filler are similar because they are both polysaccharides. The influences of the filler content on the morphology. viscosity, mechanical properties, dynamic mechanical properties, water vapour permeation and thermal degradation of GPS/CN composites were studied. It was shown that the obvious improved effect on the tensile strength, storage modulus, glass transition temperature, water vapour barrier and thermal stability could be attributed to the filler/matrix interactions, which occurred when CN was dispersed uniformly in the GPS matrix at low content. However, higher CN loads (8 wt.%) resulted in the aggregation of CN in the composites. (C) 2009 Elsevier Ltd. All rights reserved.