Wood pulp reinforced thermoplastic starch composites

摘要

Thermoplastic starch is potentially a low cost alternative biodegradable plastic that is readily avaiable material, but owing to its poor mechanical properties and high sus-ceptibility to waterial, but owing to it poor mechanical properties and high sus-ceptibility to water, its actural replacement of the polymers currently in use is limited. In this study we investigated the employment of wood pulp as fiber reinforcement for thermoplastic starch. The composites were prepared with regular cornstarch plasticized with glycerol in the presence of fiber. The matrix compositions were starch/glycerol 70/30, 80/20 and 90/10 (w/w). The wood pulp fiber content was varied from 5 to 15% by weight. The composites were characterized by mechanical tests, scanning electron microscope and water absorption experiments at 97% relative humidity. It was found that the addition of fiber led to a large increase in the elastic modulus and tensile strength and that these effects are very dependent on the glycerol content. The water absorbed by the composites was sharply reduced by the addition of pulp, and seems to be independent of the amount of glycerol and pulp content. Scnning electron microscopy of fracture surfaces revelaed that fibvers were well dispersed in the matrix and were strongly bonded to it.