Reinforcing thermoplastic polymers with natural fibres tends to improve tensile and flexural strength but adversely affect elongation and impact strength. This limits the application of such composites where toughness is a major criterion. In the present work, bamboo fibre reinforced polypropylene (PP) composites were prepared with bamboo fibre content varying from 30% to 50% with improved impact resistance. Homopolymer and copolymer PP were used as the matrix polymer and an elastomer was used (10% by wt.) as an additive in the formulation. Copolymer based composites exhibited superior elongation and impact strength as compared to homopolymer based composites. The adverse impact of elastomer on tensile and flexural strength was more pronounced in homopolymer based composites. The study suggested that the properties of the bamboo composites can be tailored to suit different applications by varying reinforcement and elastomer percentage.

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In this work, we have compared the mechanical and thermal properties PVC/TPU blends with variable weight ratio prepared using single screw and twin screw extruder. Two grades of TPUs differing in hardness (Shore A hardness 66 and 85) are used in making the blends. The tensile strength of PVC/TPU-1 and PVC/TPU-2 blends obtained from twin screw extruder is higher by 39% - 98% and 89% - 143% than that obtained from single screw extruder, which indicates intimate mixing of two phases in twin screw extruder. Beyond 30 % of TPU content, the blends of TPU-2 (high hardness grade) exhibit relatively high modulus compared to blends of TPU-1. The blends prepared by twin screw extruder were relatively harder. The rebound resilience of blends prepared by twin screw extruder was found to be always more. The rebound resilience of PVC/TPU-1 blends is relatively more compared to PVC/TPU-2 blends due to more number of soft segments in TPU-1. The blends were also characterized by abrasion resistance, MFI, DSC and TEM.