Thermoplastic starch–cellulosic fibers composites: preliminary results

In this work we use cellulosic fibers from Eucalyptus urograndis pulp as reinforcement for thermoplastic starch in order to improve its mechanical properties. The composites were prepared with regular cornstarch plasticized with glycerin and reinforced with short cellulosic fibers (16% w/w) from bleached pulp. The fibers were added to the thermoplasticized starch directly in an intensive batch mixer at 170°C. The mixture was hot pressed in 2–3 mm-thick plates and then cut to prepare the specimens for mechanical tests. The composite was analyzed by thermal analysis (DSC and TGA) and water absorption experiments. The composite shows an increase of 100% in tensile strength and more than 50% in modulus with respect to non-reinforced thermoplastic starch. Scanning electron microscopy of fractured surfaces revealed a very good adhesion between the fibers and the matrix. The results obtained show clearly the advantages in the use of thermoplastic starch reinforced with cellulosic fibers, a natural, cheap and abundant material.