Hybrid Reinforcement of PLA With Pumice and Basalt Fiber: A Synergistic Approach

ABSTRACT This study investigates the mechanical, thermal, and tribological behavior of PLA‐based composites reinforced with basalt fiber (BF) and pumice, along with matrix modification using Joncryl. By systematically combining hybrid reinforcement and matrix modification strategies—typically examined separately in the literature—this study presents a novel approach that reveals their synergistic effects. Pumice was silanized to enhance matrix‐filler bonding. FTIR analysis confirmed the successful silanization of pumice particles by the appearance of characteristic –NH ₂ , Si–O, and Si–C bond peaks, indicating effective surface functionalization. The highest tensile strength of 87.1 MPa was achieved in the composite containing 3 wt% pumice and 10 wt% BF, which further increased to 98 MPa with the addition of 2 wt% Joncryl, indicating a significant synergistic effect. In adhesive wear tests, the hybrid composite containing 3 wt% pumice and 10 wt% BF showed no sudden coefficient of friction (COF) increase up to 100 m, indicating a significant improvement in wear resistance. With the addition of 2 wt% Joncryl, the COF values decreased further, confirming enhanced interfacial adhesion and protection of the matrix during sliding. DSC results showed that the addition of 2 wt% Joncryl to the hybrid composites (BF + 3 wt% pumice) increased the glass transition temperature from 51.3°C to 58.7°C while decreasing the relative degree of crystallinity from 101.4% to 79.6%, indicating that enhanced interfacial interactions restricted PLA chain mobility and hindered crystalline ordering. These findings offer a promising route to eco‐friendly PLA composites using local materials, with potential for advanced applications.