Preparation And Property Study Of Thermal Conductive PP Composites

Insulating and thermal conductive polymer has being playing an important role in microelectronic packaging, LED lighting, chemical equipment, electrical machinery and aerospace industry owing to its favorable thermal conductive and insulating property. In this paper, insulating and thermal conductive polypropylene composites were prepared by using polypropylene as matrix and Zn O, BN as fillers, and the main contents are as follows:In chapter two, Triethoxyoctylsilane was used for the surface treatment of Zn O, and the result showed that the oil-absorbed value of modified Zn O was much lower and the melt index of Zn O/PP composites was increased, which explained the good compatibility between Zn O and matrix and the favorable surface treatment technology. The modified Zn O was then filled in PP, when the mass ratio of 3-micron to 40-micron zinc oxide was 1:3 and the total loading volume fraction was 40%,the thermal diffusion coefficient of the resultant composites was up to 0.685mm2/s and thermal conductivity 1.39W/m·K,volume resistance, melt index, tensile strength, bending strength, impact strength, elongation at break was 2.1×1010Ω?m, 0.3g/10 min, 20.4MPa,25.5MPa,1.2kj/m2and1.1%,respectively.TG analysis showed that Zn O could improve the thermal stability of PP.In chapter three, epoxy resin and organic amine were used for the microencapsulation surface treatment of BN, the water contact angle of the resultant BN was increased while the oil-absorbed value and sedimentation rate was reduced, the melt index of the BN/PP composites was also higher, compared to unmodified BN, which explained the good compatibility between Zn O and matrix and the favorable surface treatment technology. When the modified BN was filled in PP and the loading volume fraction of modified BN was 25%,the thermal diffusion coefficient of the resultant composites was 0.664mm2/s and thermal conductivity 1.11W/m·K, melt index 1.3g/10 min.Zn O was then mixed with BN/PP composites to further enhance its thermal property, when the loading volume fraction of Zn O was 10%,the thermal diffusion coefficient, thermal conductivity, melt index, tensile strength, bending strength, impact strength, elongation at break, initial decomposition temperature and maximum decomposition rate temperature was o.945mm2/s,1.66W/m·K,1.2g/10 min,16.9MPa,21.8MPa,1.7kj·m-2,0.3%,400℃and 463℃,respectively.