Poly styrene-co-acrylonitrile (SAN) is a glassy thermo plastic material with industrial importance towards developing polymeric products for structural applications. The drawback of this copolymer is its limited impact strength. This work aims at improving the impact strength of SAN by blending it with liquid isoprene rubber (LIR). Compositions of SAN/LIR viz., 85/15, 80/20, 75/25 and 70/30 were melt mixed and subjected to dynamic vulcanization in a Haake Rheomixer using peroxide as vulcanizing agent. The mechanical properties such as, tensile, flexural and impact strength of all the compositions were measured as per ASTM standards and was compared with neat SAN. The effect of LIR on the thermal properties and phase morphology of the blends were characterized using dynamic mechanical analyzer and scanning electron microscope respectively. Authors observed that, by blending 20% LIR with SAN, there was 6% increase in elongation at break and 45% additional impact modification with a reduction in tensile and flexural moduli. Its microscopic morphology depicted globular and fine dispersion of LIR particles in SAN matrix, which is a well-known phase morphology favoring the toughness. This study offers a novel approach in developing thermoplastic vulcanizates (TPVs) using liquid rubbers in order to toughen the SAN. Which is also an energy efficient process compared to the TPVs developed using solid elastomers.

Keywords- Styrene acrylonitrile (SAN), dynamic vulcanization, liquid isoprene rubber (LIR), impact modification, thermoplastic vulcanizate (TPV), toughening,