Thermal & morphological evaluation of linear and radial SEBS-polypropylene blends

Abstract

Blending of two or even more immiscible polymers is a very useful method to obtain new polymeric materials with ordered and tailored properties. Thermoplastic elastomers (TPE's) are interesting materials for various applications, including the automotive industry, due to their excellent balance between processability and physical properties, especially using hydrogenated styrene-butadiene copolymer. In the present work, two structures of styrene-ethylene/buthylene-styrene (SEBS) triblock copolymer (linear and radial) were blended with polypropylene (PP) using a process aid oil. Three different SEBS-PP ratios were evaluated. Phase behavior was studied by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and Scanning electron microscopy (SEM), which confirmed the formation of a single phase material. PP crystallinity was affected by SEBS structure causing a lamellar thinning of crystals. The SEM analysis shows that radial and linear structures of SEBS have different morphology.