Recyclability of novel dynamically cured copolyester/epoxidized natural rubber blends

Abstract

Dynamically cured copolyester (COPE)/epoxidized natural rubber blends, with 50 mol % epoxide in the natural rubber (ENR-50), were prepared and the recyclability was investigated over 5 reprocessing cycles. It was found that stiffness, modulus, tensile strength, tension set value and hardness properties increased, while elongation at break and degree of swelling decreased with the count of reprocessing cycles. In addition, the recycled blends from reprocessing all had similar particle sizes of dispersed vulcanized rubber in the COPE matrix. It was also found that the thermomechanical properties observed by temperature scanning stress relaxation (TSSR) decreased with the reprocessing cycles. Furthermore, T g of the rubber phase shifted upwards with the reprocessing cycles, while T g , T m and crystallinity of the copolyester phase remained almost unchanged.