This study provides a systematic investigation into the development of PLA-3D850 biocomposites reinforced with alkali-treated rice husk and green-synthesised titanium dioxide (TiO₂) nanoparticles, as well as their hybrid combinations, specifically for orthopaedic insole applications. The novelty of this work lies in the synergistic hybridisation of agricultural waste and bio derived inorganic nanoparticles to simultaneously enhance stiffness, strength and viscoelastic damping which remains underexplored for wearable biomedical devices. Unlike prior studies that typically focus on single-filler systems or conventional synthesis methods, the mechanical performance of PLA-3D850 biocomposites, reinforced with rice husk RH (R1–R3), TiO₂ nanoparticles (T1–T3), hybrid RH/TiO₂ (H1–H3), and virgin PLA-3D850, was evaluated for orthopaedic insole applications. TiO₂ nanoparticles significantly improved tensile strength in the T-series, peaking at 25.20 MPa (T3), surpassing the R-series maximum of 21.62 MPa (R2). The hybrid H2 achieved the highest overall at 28.62 MPa. Elastic modulus was highest in T3 (293.71 MPa). Elongation at break ranged from 16.05% (H1, highest) to 9.14% (R2, lowest). DMA revealed H1’s superior storage modulus (900 MPa) and loss modulus (142 MPa), with an onset temperature of 104.0 °C, indicating excellent toughness and energy absorption. Glass transition temperature (Tg) peaked at 123.8 °C in H3, attributed to RH/TiO₂ synergy enhancing intermolecular forces; T1 showed the lowest (88.5 °C) due to plasticiser-induced matrix weakening. The highest tan δ (0.272) occurred in T2 at Tg, reflecting enhanced damping for insoles, while H1 reduced it to 0.093, increasing stiffness and lowering energy dissipation. enabling sustainable load-bearing insoles superior to non-hybrid natural fiber PLA.
Nwangwu et al. (Sat,) studied this question.