Injection molded composites of short alfa fibers and biodegradable blends

Fully biodegradable composites made from two polymer blend matrices (SEVA-C: starch and a copolymer of ethylene vinyl alcohol; and SCA: starch and cellulose acetate) and short Alfa fibers were developed and processed by conventional injection molding into standard tensile specimens. For each kind of matrix, the influence of the reinforcement load was evaluated, using fiber amounts from 0 to 30% (wt/wt). An optimization study was carried out for the composite SEVA-C with 10% Alfa fiber. The obtained results establish that the produced biodegradable composites present a significant improvement in stiffness for both matrices. Improvements in the tensile strength were observed only for the Alfa fiber reinforced SEVA-C. However, for both matrices, the reinforcement causes a significant loss in the material ductility. Results from design of experiments (Hadamard plans) were used to explain the influence of the injection molding conditions on the mechanical behavior of the obtained composites, mainly on the stiffness values.