Effects Of γ-ray Irradiation On T700 Carbon Fiber And Its Composite Interface Performance

In recent years, T700 carbon fiber has become increasingly received attention because of its excellent performance such as high strength and high modulus. However, the fiber surface is so smooth that the interface properties of composite materials have been limited. In this paper, ⁶⁰Coγ-ray irradiation graft technology was used in order to enhance the interface properties of the indigenous T700 carbon fiber reinforced epoxy composite.The tensile strength of single fiber of untreated and irradiated T700 was tested, and the statistical average strength was calculated using two-parameter Weibull distribution method. The results indicate that the effect ofγ-ray irradiation on the strength of T700 carbon fiber body is not obvious. The interfacial properties of T700 composites were evaluated by the interlayer shear strength (ILSS), interfacial shear strength (IFSS) and flexural strength. The results show that the optimum irradiation condition should be nitrogen atmosphere and epoxy chloropropane used as grafting solution under the irradiation dose of 30kGy. It is found thatγ-ray irradiation can make the fractography of T700/epoxy resin composite more smooth, and the adhesion between fiber and resin is increased effectively. The hydrothermal aging property of T700/epoxy composite material was investigated, and it is shown thatγ-ray irradiation can deduce the damage of ILSS and flexural strength caused by ernvironment.The morphology of T700 was characterized by scanning electron microscopy (SEM) and atom forced microscopy (AFM), respectively. The fiber surface roughness was increased, and the mechanical engagement between fiber and matrix resin was enhanced. The contact angles between T700 and three kinds of liquid, such as water, ethylene glycol and diiodomethane, were measured to calculate the fiber surface energy. The results show that the contact angles decreased because of theγ-ray irradiation, and the fiber surface energy has different levels of increase with the improvement of wettability. The surface chemical elements and functional groups of untreated and irradiated T700 were observed by photoelectron spectroscopy (XPS). The results show that the value of O/C and the quantity of oxygen functional groups on T700 surface were enhanced efficiently after treatment byγ-ray irradiation graft technology. The reaction ofγ-ray irradiation grafting T700 was studied according to the results above.