ABSTRACT
The performance of fiber-reinforced polymer (FRP) composites is governed by the durability of their constituents: polymer matrix, reinforcement fiber, and the nature of the interfaces. Weather and radiation factors that contribute to degradation in plastics include the following: temperature variations, moisture, sunlight, oxidation, microbiologic attack, and other environmental elements. Cyclic exposure is an important factor when considering the in-service environment of a composite material. Diffused water in the FRP composite gives rise to some physicochemical changes in the structure of the polymer, as well as the interface. The state of the stress at the interface is quite decisive on the water absorption behavior of the FRP composites. Differential expansion of the fiber and matrix leads to the generation of thermal stress at the interface. Hence, the water absorption behavior is significantly affected when there is a cyclic variation in the environmental temperature. In a similar way, fluctuation in the relative humidity also affects the moisture diffusion characteristics in FRP composites. In this chapter, the effects of such a dynamic environment on the mechanical performance of FRP composite have been discussed.
