Study On Electromagnetism Characteristic Of Polymer Composite Reinforced With Carbon Nanofibers

Carbon nanofibers(abbreviated as CNFs) is one of fiber forms growed by chemical vapourly phase, which is a new type of reinforcement materials with semi-micron dimension that has been arisen in recent years. Carbon nanofibers not only has the intrinsic properties of general charcoal materials, but also have high electric conductivity, tube structure, large aspect ratio, in addition, it also have properties like low density, high strength, good corrosion-resistance, high temperature endurance and anti-oxidant advantagement. Carbon nanofibers own excellent physical and chemical properties, and polymers have merits of low density, runny ability and advantage of easily moulding, thus the composite of carbon nanofibers and polymer can sufficiently exert both of their merits, and obtain materials with special performances or more excellent performances.Under hydrothermal and ultrasonic conditions, this dissertation made carbon nanofibers well disperse in epoxy matrix, cast was adopted to prepare a new kind of carbon nanofibers/epoxy resin composite materials at ambient temperature. Results of studies suggested that this composite has good electrical conductivity. With the increase of weight friction of the carbon nanofibers, the resistivity of the composite presented a decrease in orders of magnitude; At the same time, the temperature-resistivity characteristic and pulling-resistivity characteristic of composite materials were also investigated in the experiment, and the change of composite resistivity with the change of temperature and stress was analyed. Results indicated that as the temperature increased, the PTC effect was found at begining, when the temperature was up to the scope of 80～100℃, the materials began to demonstrate NTC effect, and it could be observed that NTC effect was relatively more obvious than PTC effect; In process of pulling, the resistivity of composite had been on the rise all the time, in the initial stage of breaking course, a sharp increase of resistivity was observed in the composite, while at the middle stage of pulling, the resistivity of the composite slowly increased with the increase of stress. At last, electromagnetic emission effect of composites was studied, and the mechanics of the phenomenon was analyed too.