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摘要
A novel thermally conductive plastic composite was prepared from a mixture of silicon nitride (Si(3)N(4)) filler particles and an ultrahigh molecular weight polyethylene-linear low density polyethylene blend. The effects of Si(3)N(4) particle sizes, concentration, and dispersion on the thermal conductivity and relevant dielectric properties were investigated. With proper fabrication the Si(3)N(4) particles could form a continuously connected dispersion that acted as the dominant thermally conductive pathway through the plastic matrix. By adding 0-20% Si(3)N(4) filler particles, the composite thermal conductivity was increased from 0.2 to similar to 1.0 W m(-1) K(-1). Also, the composite thermal conductivity was further enhanced to 1.8 W m(-1) K(-1) by decreasing the Si(3)N(4) particle sizes from 35, 3 and 0.2 pm, and using coupling agent, for the composites with higher filler content. Alumina short fibers were then added to improve the overall composite toughness and strength. Optimum thermal, dielectric and mechanical properties were obtained for a fiber-reinforced polyethylene composite with 20% total alumina-Si(3)N(4) (0.2 mu m size) filler particles.
