Study On The Preparation Of Thermally Conductive Polyvinyl-based Plastics

PE-RT pipe is mainly used for heating connection,solar panels,floor heating,thermal cycling systems,heat exchangers,etc.Although the PE-RT pipe has good long-term pressure resistance,thermal stability,and production process without cross-Product homogeneity,low temperature resistance,and easy installation,green,recyclable and other advantages.But its thermal conductivity is low,only 0.40W/(m·K).In order to improve the thermal conductivity of PE-RT pipe,so that it can meet the practical needs of society,to enhance the PE-RT pipe thermal conductivity is necessary.Therefore,the development of a high thermal conductivity at the same time with excellent mechanical properties of the composite material for the present has a greater theoretical significance and application value.In this paper,PE-RT was used as the matrix resin,two kinds of alumina and aluminum powder with different particle diameters were used as heat-conducting filler.According to the melt-blending process,the pellets were extruded by twin-screw extruder,Machine to prepare a high thermal conductivity composite material.The influence of the particle size and the amount of Al2O3 on the thermal conductive polymer composites was studied,and coupling agent modification on the properties of PE-RT matrix composites was studied.The effects of different sizes of Al2O3 on the thermal conductivity and mechanical properties of PE-RT matrix composites were investigated.The influence of Al content and Al filler surface modification on the thermal and mechanical properties of the composites was studied.The thermal stability and crystallization properties of the composites were analyzed by DSC,and the dispersion of the filler was analyzed by scanning electron microscopy.The thermal conductivity of thermal conductive composites was predicted by three theoretical models,and the Maxwell-Eucken model is more accurate in predicting the thermal conductivity of Al/PE-RT and Al2O3/PE-RT composites in three theoretical models.The results show that the thermal conductivity of the composites can be improved by filling the PE-RT matrix with the Al2O3 single component with different particle size.The thermal conductivity of the composites increases with the increase of the content of Al2O3,The thermal conductivity can reach 0.47W/(m·K)at 15%,which is 18%higher than pure PE-RT.With the addition of Al2O3,the mechanical properties of the composites decrease.The addition of Al2O3 increases the torque of the composites and the fluidity of the composites decreases.When the content of Al2O3 is 5%and 10%,the melt flow of the composites is better,which is beneficial to the production and processing.The addition of three kinds of powdery coupling agents could improve the thermal conductivity of Al2O3/PE-RT composites,When the amount of silane coupling agent is 1.5%,the thermal conductivity and mechanical property are the best,and the other two kinds of coupling agent are 2%.When the dosage is 1%,the mechanical property is the best.The thermal conductivity of the composites is higher than that of the composites prepared by the two methods.When the filling ratio is 0.6μmAl2O3:40nmAl2O3 = 3:2,And the tensile strength,the impact strength and the elongation at break of the corresponding mechanical properties were also good,which were 20.155Mpa,2.375J/cm2,587.1%.The thermal conductivity of the composites decreases with the increase of the loading of aluminum powder,the tensile strength,the elongation at break and the impact strength decrease gradually.The thermal stability of the composites gradually improves,and the crystallization temperature of the composites Also will rise.The mechanical properties and thermal conductivity of the composites were improved by the coupling agent of two different shapes of heat conductive filler aluminum powder.The modification effect of liquid silane coupling agent on aluminum powder was better than that of powder coupling agent Treatment effect.From the micro-morphology,the impact cross-sectional morphology of the composites after the addition of aluminum powder appeared agglomeration,which is the same as that of the Al2O3-filled composites.The Maxwell-Eucken model is more accurate in predicting the thermal conductivity of Al/PE-RT and Al2O3/PE-RT composites in three theoretical models.