1.20 Hygrothermal Effects in Composites

Due to their excellent specific mechanical properties, composites are becoming more and more popular in many applications. In some cases, composites are used in harsh environment and the performance of the composites is heavily affected by relative surroundings, like moisture and heat. As a result, it is important to understand the degradation mechanism of composites in hygrothermal environment and improve the damage tolerance of composites. In this chapter, the fundamental knowledge of hygrothermal mechanism of moisture and temperature has been identified. Hygrothermal effects on mechanical properties of polymer matrix, fibers, and composites have been reviewed in details. Functions of nanofillers and surface treatments in hygrothermal environment have also been discussed. To sum up, the present chapter has emphasized the existed challenges of hygrothermal effects on composites and tried to reach a concise point from contradictory understandings.