Development and performance evaluation of sustainable 3D-Printed PLA composites reinforced with sword bean microfibers and teff straw-derived biosilica

Polylactic acid (PLA) was reinforced with glycidoxypropyltrimethoxysilane (GPTMS)-treated sword bean microfibers and teff straw-derived biosilica in sustainable hybrid composites that were created using twin-screw extrusion and fused deposition modelling. Hydrophilic reinforcements and PLA matrix interface compatibility was improved through surface treatment with GPTMS. A variety of mechanical, thermal, and water absorption tests were performed on the manufactured composites. When hybrid reinforcements were used, performance was noticeably improved. The optimal mixture of 30 vol. % microfiber and 3 vol. % biosilica (PSB2) demonstrated superior overall characteristics, yielding 126 MPa for tensile strength, 137 MPa for flexural strength, 4.55 J for impact energy, 82 Shore D for hardness, 0.45 W/mK for thermal conductivity, and 1.49 % less water absorption. The creation of an efficient hybrid reinforcement network, enhanced interfacial bonding, and uniform biosilica dispersion are the reasons behind these improvements. The constructed composites are well-suited for high-tech structural and functional uses, as the results show that they are strong, robust, thermally efficient, and moisture resistant.