Mechanical and thermal properties of copoly(styrene/acrylonitrile) compatibilised Nylon-thermoplastic elastomer blends

The effects of blend compositions on the mechanical and thermal properties of polymer blends containing Nylon 66 and a thermoplastic elastomer (TPE), Santoprene®, have been studied. A 5% styrene/acrylonitrile copolymer was added to neat Nylon, TPE, and their blends. The blends were injection moulded and the tensile and impact properties were investigated. The morphology and thermal properties of the blends were observed using scanning electron microscopy and differential scanning calorimetry, The presence of double melting temperatures showed that the Nylon 66 and TPE are immiscible. However, blending produced a modification of mechanical and thermal properties. At TPE/Nylon ratios above 50:50 the tensile properties of TPE improved. In addition the impact properties of Nylon improved above the 50:50 ratio, i.e. in the TPE rich region. Both the melting temperature and crystallinity were depressed in the region of 50:50 blend composition. The presence of two phases, which is evidence of immiscibility of the blends, was confirmed by scanning electron microscopy.