Conversion Rate and Mechanical Properties of Polymethyl Methacrylate ( <scp>PMMA</scp> ) and Its Biaxial Glass Fiber Composites for Wind Turbine Blade

ABSTRACT In this study, benzoyl peroxide (BPO) and N, N ‐dimethylaniline (DMA) were employed as a redox initiator pair to initiate the polymerization of methyl methacrylate (MMA) to shorten the demolding time and save energy consumption. The conversion rate over time aligned with typical kinetic profiles of radical polymerization, showing rapid initial growth followed by a slow termination phase. Polymethyl methacrylate (PMMA) obtained with low initiator concentration exhibited higher molecular weight and superior mechanical properties (tensile strength: 63.1 MPa; bending strength: 118.1 MPa). A lower polymerization temperature (5°C) significantly influenced the molecular weight distribution of PMMA, resulting in an approximately 38% decrease in tensile strength and a 51% reduction in bending strength compared to samples cured at 35°C. Additionally, PMMA/biaxial glass fiber (PMMA/GF) composites were prepared, demonstrating better mechanical properties than epoxy/GF. Tensile properties were highly dependent on the fiber orientation: the ± 45° configuration showed a strength of 200.0 MPa and modulus of 13.49 GPa, indicating lower strength but higher toughness, whereas the 0°/90° configuration exhibited higher values of 479.2 MPa and 21.3 GPa, suggesting higher strength but lower toughness. Finally, a 5‐kW wind turbine blade was fabricated by vacuum assisted resin infusion to validate the feasibility of the PMMA/MMA system as a liquid binary resin.