Influence of processing conditions on the mechanical properties of SEBS/PP/oil blends

A common type of thermoplastic elastomer is a blend of styrene-ethylene-butylene-styrene copolymer (SEBS) with polypropylene and mineral oil. The knowledge about the processing parameters that influence the blend of these components is important to achieve the best material properties. In this study, were evaluated the influence of screw configuration (low and high shear) and speed (200, 300, and 400 rpm), molding form (compression and injection) and SEBS type (high and low molecular weight). The specimens were characterized according to their morphology, crystallinity, thermomechanical and mechanical properties. Samples processed in a screw with more kneading zones had a lower modulus value. Compression molded specimens had lower mechanical performance than injected samples. Samples prepared with low molecular weight SEBS presented a loss of mechanical properties. It was possible to correlate processing form with all the properties evaluated. The analyzed variables influenced the morphology, crystallinity and thermomechanical properties, but had low influence on the tensile properties.