Lightweight Basalt Fiber/Polyphenylene Sulfide Composite Boards With Exceptional Mechanical, Flame Retardant, Water Resistant, and Freeze‐Thaw Resistant Properties

ABSTRACT The continuous evolution of modern architectural structures has imposed heightened demands on multifunctional composite boards that integrate exceptional mechanical strength, long‐term fire retardancy–insulation performance, and outstanding freeze–thaw resistance. In this study, basalt fiber (BF) and polyphenylene sulfide (PPS) were utilized to fabricate BF felts through conventional wet‐laid processing and thermal treatment. The formed mats were subsequently boarded and consolidated via hot‐pressing to produce BF/PPS composite boards. A systematic investigation was conducted on the mechanical properties, thermal stability, crystallinity, thermal insulation and flame retardancy, water resistance, and freeze–thaw durability of the boards. The results showed that when the BF content was 50%, the tensile strength, flexural strength, and impact strength of the composite board were 120.32 MPa, 120.51 MPa, and 22.5 kJ/m 2 . The material exhibited superior fire resistance and thermal insulation capabilities, with a thermal conductivity of 0.065 W/(m K) and a limiting oxygen index (LOI) of 35%. Notably, it displayed low water absorption (1.82%), lightweight characteristics (density: 1.25 g/cm 3 ), and a specific strength of 8.19 × 10 4 N m/kg. Remarkably, only 4.4% tensile strength loss was observed after 25 freeze–thaw cycles, confirming exceptional frost resistance. The environmentally compatible BF/PPS composite, combining outstanding mechanical properties, thermal insulation, fire safety, and freeze–thaw durability, demonstrates significant potential for enhancing building energy efficiency and structural safety. These advantages position it as an ideal candidate for applications including fire‐resistant doors, roof insulation systems, electric vehicle battery casings, and wind turbine blade components in architectural and industrial sectors.