Effects of simultaneous hygrothermal aging and thermal shock cycling on carbon fiber‐reinforced polyphenylene sulfide composite performance

Abstract The adoption and widespread use of alternative low‐to‐cryogenic‐temperature liquid fuel (ALF) storage require cost‐effective fiber‐reinforced polymer composites capable of withstanding severe conditions, including thermal shocks from refueling and simultaneous hygrothermal aging due to water contamination. This study outlines a procedure to evaluate the performance of a carbon fiber‐reinforced polyphenylene sulfide (CF‐PPS) laminate subjected to up to 500 hygrothermal shock cycles (HTSC), using liquid nitrogen as the cooling medium and boiling water as the heating agent. Comprehensive assessments—including water absorption, infrared spectroscopy, and thermal and fractographic analyses—investigated damage mechanisms and their effects on mechanical and dynamic‐mechanical properties. The laminate retained ~90% of its flexural strength and modulus after HTSC and ~80% of its residual properties post‐low‐energy ballistic impact. Glass transition temperature and storage modulus increased beyond pristine levels, while hardness and impact toughness remained above 95% and 85%, respectively. Despite HTSC‐induced degradation, increased irreversible crosslinking and thermo‐residual compressive stresses reinforced fiber‐matrix interlocking, preventing interlaminar damage and enhancing safety margins against failure. Fractographic analysis confirmed the absence of delamination, with controlled fiber pullout and matrix debonding as dominant failure modes. These findings highlight the durability of CF‐PPS laminates, denoting their suitability for ALF storage applications. Highlights Hygrothermal shock cycles test is proposed and duly conducted in CF‐PPS. CF‐PPS sustains substantial flexural properties after 500 hygrothermal shocks. Still retains significant residual mechanical properties post ballistic impact. Preserves most of Izod impact and hardness under the severest conditioning. No delamination occurs even after the most extreme imposed conditioning. Strong fiber‐matrix interaction rules debonding and pullout, delaying failure.