Silanized Rice‐Husk Nanosilica/ PLA ‐ PBS –Borassus Fiber Biocomposites: Balancing Tribological Durability With Soil‐Burial Biodegradation and Aerobic Mineralization

Abstract

ABSTRACT Biodegradable PLA/PBS composites reinforced with lignocellulosic fibers remain limited by poor fiber–matrix compatibility, moisture sensitivity, interfacial defects, and wear. The specific knowledge gap addressed here is whether coordinated GPTMS modification of microscale Borassus palm fiber and rice‐husk‐derived nanosilica can establish a hierarchical interphase that improves durability while retaining biodegradability. A 70/30 PLA/PBS blend containing 30 wt% GPTMS‐treated Borassus fiber and 0–2.0 wt% silanized rice‐husk nanosilica was prepared by melt compounding. FTIR, XRD, SEM, and XPS supported surface modification and formation of a silicon‐containing interphase. The 1.5 wt% nanosilica composite exhibited optimal performance, achieving tensile and flexural strengths of 72.60 and 111.60 MPa, respectively, and a storage modulus of 4860 MPa, representing a 64% increase over the untreated fiber composite. It also showed 0.92% void content and a 91.4° water contact angle, while its specific wear rate decreased by 72%. After 180 days of soil burial, it retained 77% of its tensile strength and achieved 46% CO 2 ‐based mineralization. Property deterioration at 2.0 wt% nanosilica identified an optimum loading threshold. These findings demonstrate that coordinated micro‐ and nanoscale interfacial engineering balances mechanical durability, moisture resistance, tribological performance, and biodegradation in waste‐derived PLA/PBS biocomposites.