Effects of hygrothermal aging on the thermomechanical properties of a carbon fiber reinforced epoxy sheet molding compound: An experimental research

• Published in: Journal of applied polymer science 2021-03, Vol.138 (11), p.n/a
• Main Authors: Zulueta, Kepa, Burgoa, Aizeti, Martínez, Iñaki
• Format: Article
• Language: English
• Subjects: Aging; Carbon fiber reinforced plastics; Carbon fibers; Carbon-epoxy composites; Composite materials; composites; Continuous fiber composites; Diffusion coefficient; Dynamic mechanical analysis; Epoxy resins; Fiber composites; Fiber reinforced polymers; glass transition; hydrophilic polymers; Materials science; mechanical properties; Moisture content; Polymers; Relative humidity; Sheet molding compounds; Test chambers; Thermomechanical properties
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.50009

Carbon fiber sheet molding compounds (C‐SMCs) are discontinuous fiber reinforced composite materials. Among them, epoxy‐based C‐SMCs are becoming relevant materials due to their high thermomechanical performance and better formability than continuous fiber reinforced composites. The thermomechanical performance of epoxy resins and epoxy based continuous carbon fiber composites have shown to be influenced by hygrothermal aging. In this work, this influence is studied for an epoxy‐based C‐SMC. Epoxy‐based C‐SMC samples were hygrothermally aged by means of accelerated conditioning, exposing them to 65% relative humidity, and 80°C in a climatic chamber. The equilibrium moisture content, as well as the moisture diffusion coefficient has been determined. The thermomechanical properties of epoxy C‐SMC have been analyzed by dynamic mechanical analysis, tensile, 3‐point bending, and short beam tests in dry and aged samples. The results showed that epoxy C‐SMC is affected by hygrothermal aging in the cases of moisture intake and its effects on Tg value, but interestingly, the hygrothermal aging did not generate any degradation effects in the mechanical response of epoxy C‐SMC. Epoxy‐based carbon fiber sheet molding compound (C‐SMC) is affected by hygrothermal aging in the cases of moisture intake and its effects on Tg value, but interestingly, the hygrothermal aging did not generate any degradation effects in the mechanical response of epoxy C‐SMC.