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Abstract: In order to improve the interfacial properties between carbon fibers and epoxy matrix, supercritical water and hydrogen peroxide were used as oxidation medium for the oxidation treatment for carbon fibers. Analysis results of X-ray photoelectron spectroscopy suggest that the oxygen content on the carbon fibers’ surfaces increases by these oxidation treatments. Scanning electron microscope and atomic force microscopy images indicate that the surface appearance of oxidized carbon fibers obviously changed. The maximal interlaminar shear strength and interface shear strength of carbon fiber/epoxy resin composite in which the fibers were treated by the supercritical water and hydrogen peroxide systems reaches 70.46MPa and 106.66MPa, increases by 13.4% and 29.6% respectively compared with untreated carbon fibers. [Copyright &y& Elsevier]

Abstract: The polyacrylonitrile-based (PAN-based) carbon fibers with progressive amounts of the oxidation treatment have been investigated using a number of surface analytical methods. The chemical content and structure of oxidated fibers have been interrogated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM), then compared to the untreated ones. The value of oxygen content increased from 4.71% to 18.84%, meanwhile, the grooves on the surfaces of the carbon fibers were deepened gradually after treatments. The results of dynamic contact angle (DCA) measurements suggest that the increase in carbon fiber surface tension is mainly because of the polar component of surface tension. After treated with increasing amounts of oxidants, the monofilament tensile strength decreased less than 3.1%. [Copyright &y& Elsevier]

Abstract: Four kinds of polyacrylonitrile-based carbon fibers were cleaned by three methods and were characterized by X-ray photoelectron spectroscopy, monofilament tensile strength test and atomic force microscopy (AFM). Experimental results of these tests reveal that the method using supercritical acetone or subcritical potassium hydroxide aqueous solution act as the processing medium shows a better cleaning effect compared to the traditional method, Soxhlet extraction with acetone. The method using supercritical acetone is more appropriate to wipe off the oxygenated contaminants on carbon fibers’ surfaces and causes a relatively smaller damage to the bulk strength of each carbon fiber. As far as treating method using the subcritical alkali aqueous solution, it can thoroughly remove silicious contaminants on the surfaces of treated fibers. [Copyright &y& Elsevier]

Highlights: [•] A new chemical grafting method for carbon fibers was proposed. [•] The oxidation system adopts K2S2O8 and AgNO3. [•] The interfacial shear strength (IFSS) of carbon fiber increased by 61%, and the interfacial adhesion increased with dendritic generation number. [•] The tensile strength of carbon fiber does not decrease distinctly. [•] The treatment conditions are mild and convenient. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]