Polycarbonate, Abs, Polypropylene, Thermal Conductivity And Flame Retardancy

As the science progress, plastic material becomes a new candidate of electrical and thermal conductive materials. The application areas of thermal conductive plastic become more and more extensive. Especially, the information industries, which have been developing vigorously in recent years, has provided a new development space for the thermal conductive plastic. The theoretical studies on thermal conductive plastic are not satisfied. The method of increasing thermal conductivity is only physical filling. So that the thermal conductivity is not high enough and mechanics properties drop greatly. The theory on prediction of thermal conductivity is just limited in experiential simulation. Research and development on Nano-materials for thermal conductivity, fabrication of high thermal conductive polymer, and exploring on the conductive mechanics of polymer will become the new study aspects to improve thermal conductivity of plastic.Polycarbonate(PC), Acrylonitrile-butadiene-styrene terpolymer(ABS), PC-ABS alloy and polyproylene(PP) were used as matrices. Various inorganic fillers including alumina, silicon carbide (SiC) and bismuth oxide (BiO) were added to the matrices alone or in combination. Samples were squeezed granulation by two-screw extruder and shaped by injection molding to investigate the effects of variety, shape and volume of the filler on thermal conductivities, mechanics and insulation properties. Flame retardant properties of PC, ABS, PC/ABS and PP matrixes were studied using magnesium hydroxide and red phosphorus as flame retardant.The thermal conductivities of PC, ABS, PC/ABS and PP were increased obviously after filling. That of PC increased from the original of 0.2 to 0.528 W/(mK) with 30%-50%Al₂O₃ be filled, and that of PC/ABS filled with 30%SiC and 30%BiO increased to 1.099 W/mK and 1.226 W/(mK), respectively. The fillers with higher aspect ratio are benefit to the mechanical properties and the forming of connectivity. The thermal conductivitiy of PP increased from the original of 0.119 to 0.595 W/(mK). The thermal conductivitiy multiplied 4-6 times.Oxygen index of PC matrix are more than 26, and the PC matrix can selfextinguish. In the formulation of flame retardant, oxygen index are 29.8-34.6, compared to that without flame retartand, it is clearly enhanced. It indicates that red phosphorus is an effective flame retardant and can be applied as flame retardant additives.The better crystal states for PP are able to effectively improve conductivity property. However, the crystal state does not contribute much to the PC matrix.Electric volume resistivity of oxide particals filled PC ABS PC/ABS and PP matrices is higher than 10¹⁵Ω. It is satisfied to be an insulating material, and is a normal insulating material.