PE-LLD/Al_2O_3导热复合材料的制备及性能

Preparation and Properties of PE-LLD/Al_2O_3 Thermal Conductive Composites

通过哈克密炼–模压成型法制备了线型低密度聚乙烯(PE-LLD)/Al_2O_3复合材料,并在不同温度条件下对复合材料的导热性能进行研究。通过扫描电子显微镜、热失重分析仪、差示扫描量热仪、激光导热仪和精密阻抗分析仪研究了复合材料中Al_2O_3的分散性及复合材料的热稳定性、熔融行为、导热性能和介电性能。结果表明,Al_2O_3均匀分散在PE-LLD基体中;添加微米级Al_2O_3后,复合材料的熔点和熔融焓变化不大,热稳定性能有所提高;当Al_2O_3添加量为100份时,复合材料的热导率为1.426W/(m·K),比纯PE-LLD的热导率提高218.0%;随着温度的升高,Al_2O_3的添加量越多,复合材料的热导率降低越明显;随着Al_2O_3添加量的增加,复合材料的介电常数和介电损耗增大,在低频时增加更明显。

Linear low density polyethylene (PE-LLD)/Al2O3 thermal conductive composites were made by Haake mixinghot pressing method. The thermal conductivity of the composites at different temperatures were also studied. The dispersion,thermal stabilities and melting behaviors,thermal conductivity and dielectric properties of the composites were measured by SEM,TG, DSC,laser thermal conductivity analyzer and precision impedance analyzer. The results show that the Al2O3 particles are uniformly dispersed in PE-LLD matrix. The melting point and melting enthalpy of the composites change little with the addition of micro- Al2O3,the thermal stability of the composite increases after adding micro-Al2O3. When the amount of micro-Al2O3 added is 100 phr, thermal conductivity of the composite is 1.426 W/(m · K),218.0% higher than that of the PE-LLD matrix. The higher the content of micro-Al2O3,the more obvious the thermal conductivity of the composites decreases with the increasing temperature. The dielectric constant and dielectric loss of the composite increases with the increasing micro-Al2O3,especially at low frequency.