Mechanical, moisture absorption, and biodegradation behaviours of bacterial cellulose fibre-reinforced starch biocomposites

In this work, bacterial cellulose (BC) nanofibres were used as the biodegradable reinforcement. The BC nanofibres were incorporated in the starch plasticised with glycerol via a solution impregnation method. Tensile properties of the BC/starch biocomposites were tested and compared with those of the unreinforced starch. Moisture absorption of the biocomposites under 75% RH at 25 degrees C was analysed. The kinetics of sorption-diffusion process was investigated and typical kinetic parameters D, k, and M(infinity) were determined. Additionally, the BC/starch biocomposite (15.1 wt.% BC) and starch were submitted to biodegradation by soil burial experiments in perforated boxes. Tensile strength after exposure to moisture and microorganism attacks was measured. It is found that the moisture sorption mechanism in the BC/starch biocomposites follows a Fickan diffusion mode. The presence of BC nanofibres improves the tensile properties and the resistance to moisture and microorganism attacks. The mechanisms behind these phenomena are discussed in this paper. (C) 2009 Elsevier Ltd. All rights reserved.