Changes in Mixing Torque, Mechanical and Dynamic Rheological Properties of Epoxidized Natural Rubber and Copolyester Blends as Affected by Epoxidized Natural Rubber Contents

Abstract

Thermoplastic natural rubber (TPNR) based on epoxidized natural rubber with 30 %mol epoxide (ENR-30) and copolyester (COPE) blends was prepared in a molten state by using roller rotor internal mixer. Effect of various ENR contents on mixing torque together with mechanical and dynamic properties of the ENR-30/COPE blends was investigated. It was found that the mixing torque and complex viscosity increased with increasing contents of the ENR in the blends. This was due to higher polarity the ENR molecules caused interaction and entanglement of the ENR molecular chains with higher viscosity. Furthermore, improvement of elastomeric properties of the ENR-30/COPE blends was clearly observed, especially in the blends with higher proportion of the ENR. These improved elastomeric properties with high elongation at break, low tension set and high storage modulus together with low tan δ. This observation correlated to higher elastic component in the blend caused promoting higher elastic response in combination with increasing of interaction between the ENR and the COPE phases.