Roles of Interfaces and nano-fillers on environmental durability and structural integrity of FRP composites

Abstract

The interfaces of composite materials play an important role to sustain the structural integrity of the system. The health of interphase/interface determines the reliability and durability of the composite systems in the service life. It has only been during the last few decades that applications of FRPs have become so rapidly growing that tailoring the well-bonded and durable interfaces has become a curious concern. An uncontrolled and non-uniform degradation at micro- and macro-levels manifests in the interphase because of different environmental conditions during service life. These may restrain its uses in the short term and also in the long-term reliability of the material. The predicted mechanical behaviour may alter during service life because of changes in the nature of the interface. Any changes in the interface might have substantial implications on its performances. The precise mode of failure is a function of the status of environmentally conditioned interfaces and time of exposure, thus complicating the prediction of its performances and behaviour. The interface is the most highly stressed region of composite materials. The important roles of interface necessitate a critical and comprehensive understanding of environmentally conditioned interfaces in FRP composite systems. It is reasonably assumed, the molecular structure here is dynamic in nature at the interfacial area, which is different from the bulk polymer matrix. The changes occurring at the interface are highly sensitive and susceptible to degradations under different environmental conditionings. Since the interphase is a region of chemical inhomogeneity, thus it provides an easy path of the system for becoming more susceptible to thermal, chemical, thermochemical and mechano-chemical degradations. Interfacial durability is a primary factor because environments to which the FRP composite is exposed can degrade interfacial adhesion as well as properties of the materials as a whole.