Influence of Rice Husk Ash on the Properties of Dynamically Cured ENR/TPS Biocomposites

This study investigates the influence of rice husk ash (RHA) on the properties of dynamically cured epoxidized natural rubber (ENR) and thermoplastic starch (TPS) biocomposites. ENR/TPS blends were prepared at a 50/50 weight ratio, incorporating RHA as a reinforcing filler at varying loadings (10–50 phr). The results revealed that the addition of RHA enhanced tensile strength and modulus, with optimal reinforcement observed at 20 to 30 phr. However, excessive RHA content led to filler agglomeration, reducin g mechanical performance. Thermogravimetric analysis (TGA) and temperature scanning stress relaxation (TSSR) indicated that thermal stability increased with RHA content up to 20 phr; however, a decreasing trend was observed with further increases in RHA loading, particularly in the degradation of TPS and ENR components. Biodegradability assessments through soil burial and accelerated weathering tests demonstrated that composites with higher RHA content exhibited greater weight loss, confirming enhanced envi ronmental degradation. Morphological analysis revealed a phase-separated sea-island structure, with RHA particles distributed within both the ENR and TPS phases, as well as at their interfacial regions. The study highlights the potential of RHA as an eco-friendly filler that enhances mechanical properties while promoting biodegradability, making ENR/TPS biocomposites suitable for sustainable material applications.