Freeze–Thaw Resistance of Glass Fiber and Carbon/Glass Hybrid Reinforced Vinyl Ester Composites for Marine Applications

ABSTRACT Glass fiber‐reinforced polymer (GFRP) and hybrid fiber‐reinforced polymer (HFRP) composites have been widely employed in marine engineering. However, their performance degradation after freeze–thaw cycling (FTC) poses potential safety risks for engineering applications. This study used GFRP and carbon/glass HFRP laminates fabricated with different material systems and stacking sequences. Following preconditioning in distilled water for 14 days at 70°C, the composites were subjected to FTC, with temperature ranging from −40°C to 30°C. At the different aging stages, the mechanical properties were assessed through tension, compression, flexure, in‐plane shear and interlaminar shear tests, complemented by Dynamic mechanical analysis (DMA), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) observation. The mechanical test results indicate that both GFRP and HFRP experience pronounced degradation after moisture preconditioning, with compressive strength (up to −19.62%) and flexural modulus (up to −21.42%) exhibiting the greatest reductions after 20 FTCs. Compared with GFRP, HFRP incorporating suitable carbon fiber type and hybrid configuration demonstrates improved resistance to mechanical degradation. In addition, a pronounced reduction of glass transition temperature () has been observed, while no significant changes in the chemical structure are observed throughout the aging. The SEM observations further elucidate the dominant degradation mechanisms, including interfacial debonding, fiber pull‐out, and matrix microcracking.