Aramid resin/carbon fiber composites with integrated performance of flexibility, strength, temperature resistance and flame retardancy

Developing carbon fiber (CF) composites that integrate flexibility, strength and extreme environmental adaptability has emerged as a new challenge, holding strategic significance for advanced high-tech fields. However, conventional polymer resins (e.g. polyurethane) employed in flexible CF composites exhibit inherent performance limitations in meeting the above requirements. Herein, heterocyclic aramid (HA), which has good flexibility and strength, inherent temperature resistance and good flame retardancy, is developed to prepare CF composites with carbon fabrics by solution impregnating and layer-by-layer stacking technique. The interfacial adhesion of the composites was evaluated at three different dimensions (fiber/HA, yarn/HA and fabric/HA) using microbond, yarn pull-out, and T-peeling tests. The flexural strength and modulus measured at three different temperatures (−55 °C, room temperature and 200 °C) show only a slight variation, revealing low and high temperature applicability. Dynamic impact testing showed that the composite with a high HA content has excellent impact toughness. The limiting oxygen index (LOI) is greater than 80 %, showing excellent flame retardancy. The composites are thermally stable up to 450 °C. This work demonstrates that HA as an efficient polymer resin can be successfully combined with CF fabric to prepare CF composites with integrated performance of flexibility, strength, temperature resistance and flame retardancy, showing the potential for applications in extreme environments.