Material propertiesProperty correlations for dynamically cured rice husk ash filled epoxidized natural rubber/thermoplastic polyurethane blends: Influences of RHA loading

Novel thermoplastic vulcanizates based on thermoplastic polyurethane (TPU) and epoxidized natural rubber (ENR) were prepared with rice husk ash (RHA) filler. Therefore, two major renewable resource materials (i.e., ENR and RHA) were exploited. Influences of RHA loading on mechanical, morphological, thermal and dynamic properties of dynamically cured ENR/TPU blends were investigated. It was found that the RHA showed good dispersion and was mainly localized in the ENR phase. Increasing the RHA loading led to the formation of larger ENR domains dispersed in the TPU matrix. Also, migration of the RHA particles from ENR to TPU phases was observed, resulting in reduced strength properties. It was found that the RHA acted as a nucleating agent in the TPU matrix and could accelerate the crystallization of TPU. Additionally, stress relaxation of the blends was evaluated by temperature stress scanning relaxation (TSSR). Higher relaxation stresses or raised relaxation curves were observed with increased RHA loadings in the dynamically vulcanized ENR/TPU blends.