Abstract
Novel thermoplastic vulcanizates based on copolyester (COPE) and epoxidized natural rubber with 30 mol% epoxide (ENR-30) were prepared with various blend ratios and their properties were investigated. The main target was to prepare the dynamically cured COPE/ENR-30 blends with low hardness (lower than 80 Shore A) but superior in damping properties. The mixing torque of the blend mixer was captured and it was found that increasing the fraction of rubber increased the final mixing torque. Dynamic mechanical properties of the blends were also determined. It was found that with increasing rubber proportion, storage modulus and complex viscosity were increased but tan δ was decreased. In addition, morphology of the blends shows increasing size of vulcanized rubber domains dispersed in the thermoplastic matrix with increasing of rubber proportion. However, the strength properties decreased in terms of Young’s and 100 % moduli, tensile strength, elongation-at-break, and hardness. This might be attributed to the increasing size of vulcanized rubber domains. Enhanced rubber elasticity and damping properties were observed with increasing rubber content in the blends, as indicated by decreased tension set and tan δ. Furthermore, temperature scanning stress relaxation results show that with increasing rubber content the blends had their relaxation curves shifted upwards and thermal resistance increased. In addition, thermal properties characterized by DSC show the decreasing heat of crystallization (H) of COPE, or decreasing crystallinity, with increasing rubber content.
Published Version
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