Interfacial characterization, control and modification of carbon fiber reinforced polymer composites

Fibrous carbon materials have been attracted many researchers' attentions. Carbon fibers have been developed as one of the most important industrial materials for modern science and technology since 1960s [1]. Due to the superior mechanical properties including high-specific strength and modulus, low density and thermal expansion, heat resistance, and chemical stability, carbon fibers as reinforcement materials have provided the impetus for researchers in developing high-performance composite materials. Nowadays, carbon fiber reinforced plastics (CFRP) are widely applied in the industries of aeronautic, aerospace, sporting goods, as well as new energy.The region between the fibers and matrix, contains unique micromechanical properties, is characteristically called the interphase and influence the bulk composite properties. Interface between fibers (reinforcements) and matrix is an important component for CFRP which may govern the CFRP performances [2]. For example, the interphase determines the off-axis strength and impact toughness of CFRP, environmental stability of CFRP and functional performance of CFRP. The effect of interface on composite can be achieved by regulating the composition, structure and distribution of the interface [3]. It has been proved that there has an optical interface for polymer based composite through the match of composite interface, reinforcement and polymer matrix. However, in terms of the smooth surface and chemical inertness of carbon fiber, the interface between carbon fiber and resin matrix is unsatisfactory. The interface should be modified and carefully controlled, which can be through by increasing the surface polarity of carbon fiber, improving the wettability between carbon fiber and resin, as well as promoting the chemical reaction. Obey these principles, the interfacial modification methods have been well developed.The universality of carbon fiber and polymer matrix, and the variability of the composite material forming process result in the complexity of polymer-based composites interface problems. Meanwhile the scale of the interface region is very small, it has great difficulty in characterizing the chemical structure, physical properties and mechanical characteristics. Recently, a series of effective characterization methods have been developed and initial interface characterization system is always being improved. With interface characterization techniques, the interfacial composition, structure morphology and micro-mechanical characteristics of interface can be researched easily, which can provide the basis for studying the interface physical and chemical properties. Hence interface characterization techniques not only are theory researches, but also have important practical significance for solving practical application problems of carbon fiber composites. Interface characterization techniques have become an important research direction of interface engineering research.In this paper, the researches in this field of carbon fiber interface were described, such as carbon fiber composite material characterization methods, interface control, and interfacial modification methods. With reference to the research achievements of a large number of scholars at present, so their current development trend were systemic concluded.