Research On The PA46-based Thermal Conductive Composite Materials

In recent years, conductive plastics showed a broad application prospect, which were highly prized. In this article, the preparation methods and properties of PA46-based thermal conductive composites were studied in order to improve the performance of thermal conductivity and satisfy application requirements.PA46was selected as the matrix, and expanded graphite and carbon fiberand were selected as the filler. PA46composites filled with graphite-, carbon fiber and both of them were prepared by the method of melt blending and injection molding. The content, and modified methods of fillers were preliminarily explored respectively. The performance of thermal conductivity, mechanical property and microstructure of thermal conductive composite materials were analyzed.With the increasing of the content of graphite filler, the thermal conductivity of PA46-based thermal conductive composites increased, however, the tensile strength, impact strength and elongation at break decreased. When the graphite mass fraction was50%, the rate of thermal conductivity was3.743W/(m·K), about13.91times that of the pure matrix;the thermal diffusivity was2.344mm2/s, about15.95times that of the pure matrix.Studies on Modification of coupling agent showed that the comprehensive properties of PA46filled with graphite composites was the best as the dosage of the KH570was1%.SEM micrographs showed that:with the increasing particle size of graphite, the dispersibility of graphite in the matrix decreased gradually.With the increasing of the content of graphite, the graphite which was dispersed in the substrate,was more likely to form the thermal chain and thermal network. Compared the experimental data with the thermal conduction model:the obtained experimental data matched better with the thermal conduction model proposed by Y.Agari.It was proved that the thermal conduction model proposed by Y.Agari was suitable for lower filled volume situations;With the increasing of the content of carbon fiber, the thermal conductivity increased, When the carbon fiber mass fraction was40%, the rate of thermal conductivity was1.49W/(m·K), about5.54times that of the pure matrix;the thermal diffusivity was0.9755mm2/s, about6.64times that of the pure matrix.Compared the experimental data with the thermal conduction model:the obtained experimental data matched better with the thermal conduction model proposed by Maxwell-Eucken. It was proved that the thermal conduction model proposed by Maxwell-Eucken was suitable for lower filled volume situations. Studies showed that, with the increasing of the content of carbon fiber, impact strength increased. Along with the increasing of calcination time, the thermal conductivity of the composite showed a trend of decline after rising first, and1h was the best; When KH570mass fraction of1%, it was the optimal coupling agent for filler content;In the graphite/carbon fiber/PA46ternary compound system, with the increasing of mass fraction of graphite, the thermal conductivity of the composite slowly increased. When two kinds of filler in EG/CF was30%:10%, the performance of thermal conductivity was the best; When EG/CF mass fraction of25%:15%, impact strength and tensile strength of the composite were48.16KJ/m2and43.82MPa, which reached maximum.