Investigation on the thermal performance of MgO-filled basalt Fiber/PLA composites for high-temperature industrial applications

• MgO nanoparticles enhance thermal and mechanical properties of basalt fiber/PLA composites. • L3 composite shows a 79.3% rise in thermal conductivity and 86.18% lower thermal expansion. • Mechanical strength improves with 8.63% higher tensile and 38.24% higher impact resistance. • TGA confirms 11°C higher degradation temperature, ensuring better thermal stability. • Suitable for automotive, electronics, and high-temperature industrial applications. This study presents a novel approach to enhancing the thermal and mechanical performance of biodegradable polymer composites by integrating magnesium oxide (MgO) nanoparticles into basalt fiber-reinforced polylactic acid (PLA) matrices. Addressing the growing demand for sustainable, high-performance materials in high-temperature industrial settings, this work focuses on developing lightweight composites that combine environmental responsibility with advanced functional properties. The composites were fabricated with varying MgO nanoparticle contents (0–16 g), while maintaining a constant basalt fiber reinforcement to systematically evaluate the effect of MgO on structural and thermal behavior. Notably, the L3 formulation (3% MgO) exhibited the most significant enhancements, with a tensile strength of 154.94 MPa (7.79%), flexural strength of 159.21 MPa (8%), impact strength of 32.45 kJ/m² (28%), and Shore D hardness of 132 (13,6%), highlighting its mechanical superiority. Thermal characterization revealed a high thermal conductivity of 0.142 W/mK, a low coefficient of linear thermal expansion (1.14 × 10⁻⁵ /°C), and a heat deflection temperature of 163°C. Enhanced thermal stability was confirmed by a peak degradation temperature of 378°C and a final residue of 14%. Scanning electron microscopy confirmed improved fiber–matrix adhesion and reduced microstructural defects. The novelty of this work lies in the synergistic use of MgO and basalt fibers in a PLA matrix, offering a sustainable route to high-temperature composite design. These composites are highly suitable for demanding applications such as automotive under-the-hood parts, electronic enclosures, structural components in thermal environments, and industrial insulation panels. Therefore, this study provides an innovative and eco-friendly solution to current limitations in thermal engineering materials by delivering high-performance, bio-based composites with broad industrial applicability.