Thermoplastic Starch‐Based Biocomposites Reinforced With Rice Husk Ash: Influence of Natural Rubber Type and Dynamic Vulcanization

ABSTRACT This study investigates the development of a biobased thermoplastic elastomeric biocomposite based on thermoplastic starch (TPS) dynamically vulcanized with natural rubber (NR), epoxidized natural rubber (ENR25 and ENR50), and reinforced with 20 phr rice husk ash (RHA). The effects of rubber polarity and filler incorporation on mechanical, thermal, and environmental performance were comprehensively examined. Among all formulations, ENR50/TPS/RHA20 exhibited the most balanced properties, achieving tensile strength of 5.3 MPa and elongation at break of 410%, compared to 1.0 MPa and 440% for NR/TPS. TSSR analysis revealed superior thermal elasticity with an initial stress of 0.18 MPa and high relaxation temperatures ( T 10 ≈ 80°C, T 50 ≈ 155°C, T 90 ≈ 190°C). Thermogravimetric results indicated a final degradation temperature of 421°C and 9.8% char residue, confirming improved thermal resistance. Additionally, ENR50/TPS/RHA20 showed reduced water absorption (∼22.5% at 72 h) and minimal weight loss (