Effect of chitin addition on injection-molded thermoplastic corn starch

A new type of biodegradable starch-based composites was prepared by injection-molding using glycerol and water as plasticizers. Chitin flakes, obtained from shells of Penaeus schmitti, were used as reinforcing phase. The effect of chitin content on the structural and tensile properties of the composite samples was examined after conditioning at 28 degreesC and 80% relative humidity for 30 days. In general, chitin incorporation into the starch matrix resulted in materials with higher modulus and decreased elongation at break. Wide-angle X-ray diffraction and differential scanning calorimetry evidenced a significant decrease in crystallinity in the composite samples in relation to the unfilled starch material. Contact angle measurements revealed that the addition of chitin contributes to the improvement of water resistance of the composite samples when compared to injection molded starch alone. (C) 2004 Wiley Periodicals, Inc.