PS/LIR dynamic vulcanization: new approach in TPV development using liquid rubber for impact modification

Polystyrene (PS), a widely known amorphous, transparent, glassy, thermoplastic material, is one of the industrially significant polymers for its wide range of applications from packaging to commodity articles. PS is also well-known for its critical drawback of brittleness. This investigation aims towards improving the impact strength of PS by blending it with liquid isoprene rubber (LIR). PS/LIR compositions viz., 85/15, 80/20, 75/25 and 70/30 were mixed and dynamically vulcanized using Haake Rheomixer using sulphur-based vulcanizing system. The dynamically vulcanized blends were subjected to tensile, flexural and impact testing along with thermal and microscopic characterization. From the experimental data, it was evident that there was 110% increment in impact strength of PS matrix with the presence of 15% parts by weight of dynamically vulcanized LIR. The blend with 30% LIR content showed an increased thermal stability of matrix but with a reduction in tensile and flexural strength. The SEM image exhibited the dispersion of fine-sized spherical particles of LIR in PS matrix which is conducive in toughness enhancement. This study offers a novel approach in developing the TPV which is based on oligomer rubber. Also, it is energy efficient approach over solid elastomers.