Preparation And Properties Of High Impact Polystyrene Thermally Conductive And Insulation Composites

High impact polystyrene?HIPS?is an engineering plastic with good processability,corrosion resistance,and good tensile and bending properties.Due to its low price compared to other engineering plastics,HIPS special products have become the focus of development in recent years.The newly developed HIPS products are comparable to other engineering plastics in some application fields,but due to their low thermal conductivity,which limits the application of HIPS plastic products in the direction of heat dissipation of electronic components and industrial heat exchanger,therefore,the development of thermally conductive insulated HIPS plastics is of great significance for expanding its application.In this paper,firstly,HIPS is used as the resin matrix,BN and AlN treated with KH792 surface treatment are used as heat-conductive fillers,and HIPS/BN composites and HIPS/AlN composites were prepared by extrusion process.The surface treatment effect of the coupling agent of the thermally conductive fillers and the thermal conductivity,mechanical properties,thermal stability and processing properties of the filled HIPS composite were characterized.At the same time,the effects of the addition of two kinds of thermally conductive fillers on various properties were studied.The results show that KH792 is coated on the thermally conductive fillers after surface treatment,and the oil absorption value of the fillers is significantly reduced,which can effectively improve the compatibility of the thermally conductive fillers with the HIPS resin matrix.The thermal conductivity of HIPS composites increases with the increase of the amount of thermally conductive filler.The thermal conductivity of HIPS/BN composites is 1.24 W/m·K at 50wt%BN.and HIPS/AlN composites thermal conductivity were reached 1.46 W/m·K when50 wt%AlN was added,which was significantly higher than pure HIPS.Filled HIPS with BN and AlN will reduce the mechanical and processing properties of HIPS,but improve the thermal stability of HIPS composites.In general,the thermal conductivity of AlN reinforced composites is better than BN when the same amount of filler is added.When the addition amount of BN and AlN is 20-35wt%,the overall performance of HIPS/BN composite material and HIPS/AlN composite material is better,and the high thermal conductivity is obtained while taking into account the good mechanical and processing properties of the material.On this basis,HIPS/BN/Al2O3 composites and HIPS/AlN1/AlN2 composites with different filler ratios were prepared by adding flaky BN and spherical Al2O3 or using AlN compound fillers with different particle size.The effects of the proportion of fillers of different types and sizes on the properties of HIPS composites were investigated.The results show that the thermal conductivity of HIPS composites is improved by compounded of different types or sizes of fillers.The mechanical and processing properties of the composites of flake BN and spherical Al2O3 have certain improvement effects.The processing properties of the composites were improved when AlN was mixed with different particle sizes,but the mechanical properties were not significantly improved.The HIPS/BN/Al2O3 composites have the highest thermal conductivity when the ratio of BN and Al₂O₃ is 7/3,which is 1.02 W/m·K.And when the ratio of AlN1/AlN2 is 6/4.The HIPS/AlN1/AlN2 composite has the highest thermal conductivity of 1.4 W/m·K.HIPS composites filled with a single thermally conductive filler or compounded with fillers,its insulation performance has little effect.The composite materials maintain a high volume resistivity,which can meet the requirements of insulation performance for product applications,and can be used in various fields where high insulation requirements are required.