Preparation And Properties Of Compound Conductive Plastics

Generally, plastics show good insulating property, therefore they are widely used inmany fields, such as wire, cable, electronics, etc. However, with the development of societyand technology, in some areas, the insulation of plastics has became a negative factor, thuspeople have been studying on how to improve conductivity of plastics. For the present, thereare mainly two kinds of this plastic. One is inherently conductive plastics, and the other iscompound conductive plastics.At present, the fiber compound conductive plastics are mostly prepared by reactiveextrusion process. The fibers will get very strong shear effect in the twin-screw extruder,which will not only make the fiber too short, but also make the equipment be worn seriously.Some foreign companies have been fabricating conductive plastics by cable coating process.In this process maximum aspect ratio of fibers could be maintained, but now no one in Chinacan break the technological bottlenecks.In this study, three kinds of conductive plastic were successfully prepared by cablecoating process, which include stainless steel fiber/polycarbonate/acrylonitrile-butadiene-styrene （SSF/PC/ABS）, carbon fiber/nylon6（CF/PA6） and nickel-plated carbonfiber/PC/ABS （NCF/PC/ABS）. The microstructure, conductivity, mechanical properties andshielding properties of these plastics were tested and analyzed, The results are as follows:（1） Before the preparation of conductive plastics, the conductive fibers were treated withsome special agents. The surface treated fibers were uniformly dispersed in the resin matrix.Compared to the conductive plastics prepared by reactive extrusion, the ones prepared bycable coating exhibit higher performance in all aspects.（2） As the fiber content increased, the conductivity of three materials are all improved.NCF/PC/ABS has the best conductivity with the volume resistivity of10^-2Ω cm. CF/PA6isthe worst one, which just has a volume resistivity of10⁰Ω cm. It is also noted thatnickel-plating can greatly improve the conductivity of CF.（3） CF has the best reinforcement effect on materials. The tensile strength of CF/PA6canbe up to247MPa, and the flexural strength can be299MPa, While the SSF has the minimalenhancement effect. The elongation at break will decrease significantly by filling any of thethree sorts of fibers. Moreover, the addition of flame retardants will affect the mechanicalproperties of the plastics, but has no influence on the volume resistivity.（4） The shielding effectiveness of NCF/PC/ABS is up to70⁹0dB, which is able to meetthe requirements of aerospace and military industry. SSF/PC/ABS can reach30⁶5dB, which is good enough to be used in general electronic equipment. In addition, the performances ofall the three kinds of conductive plastics have reached or exceeded those of foreign productsof the same types.