A Comparative Investigation of Rice Husk Ash and Siliceous Earth as Reinforcing Fillers in Dynamically Cured Blends of Epoxidized Natural Rubber (ENR) and Thermoplastic Polyurethane (TPU)

The present work aimed to develop epoxidized natural rubber/thermoplastic polyurethane thermoplastic vulcanizates (ENR/TPU TPVs) having some specific properties, i.e., good processability and dynamic properties, and excellent heat and oil resistances. A comparative study on the effects of rice husk ash (RHA) and commercial siliceous earth (SE) as reinforcing fillers on alteration and enhancement of TPV properties was performed. It was found that the RHA-filled ENR/TPU TPVs showed an improvement of thermoelastic properties with outstanding thermal resistance relative to the pure TPU. This might be attributed to the synergistic effects of the dispersed vulcanized ENR domains and the RHA particles in the TPVs. Furthermore, the RHA-filled ENR/TPU TPVs had rather similar performance, processability and physical properties to the SE-filled ENR/TPU TPV. This indicates that the RHA has great potential as a filler in thermoplastic vulcanizates, in particular with ENR that is a renewable green resource.