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

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 -NH2, 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 degrees C to 58.7 degrees 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.