为了探究Al₂O₃/聚烯烃复合材料的结构与性能，先使用硅烷偶联剂对球形Al₂O₃进行预处理，以预处理后的Al₂O₃为填料，以高密度聚乙烯（HDPE）/聚丙烯（PP）混合物（质量比5∶95）为基体，通过初混和熔融共混方法制备Al₂O₃/HDPE/PP复合材料，研究了Al₂O₃质量分数对复合材料结构与性能的影响。结果表明：填充Al₂O₃可以显著提高复合材料的导热系数，导热系数随Al₂O₃质量分数的增加而提高，当Al₂O₃质量分数为25%时，复合材料的导热系数为0.331 W/（m∙K），比纯聚烯烃基体材料提高了231%。高填充量的复合材料内部Al₂O₃颗粒间隙明显变小，这将有利于构建导热通路。较低含量Al₂O₃刚性粒子的存在可以提高聚合物结晶能力。同时，添加球形Al₂O₃能够显著提高复合材料的熔体流动速率，改善其加工性能。

In order to investigate the structure and properties of Al₂O₃/polyolefin composites, spherical Al₂O₃ was pretreated with a silane coupling agent, and high density polyethylene (HDPE)/polypropylene (PP) composites were prepared by primary mixing and melt blending with pretreated Al₂O₃ as filler and high density polyethylene (HDPE)/polypropylene (PP) mixture (mass ratio 5∶95) as matrix. The investigation of the influence of the mass fraction of Al₂O₃ on the structure and properties of the composites was studied. The results showed that the addition of Al₂O₃ significantly enhanced the thermal conductivity of the composites. Specifically, the thermal conductivity increased proportionally with the mass fraction of Al₂O₃. When the Al₂O₃ mass fraction reached 25%, the thermal conductivity of the composite measured 0.331 W/(m∙K), which was 231% higher than that of the pure polyolefin matrix material. Moreover, the presence of Al₂O₃ particles with high filler content led to a noticeable reduction in gaps within the composite, thereby facilitating the construction of thermal conductivity pathways. Additionally, the incorporation of a lower content of rigid Al₂O₃ particles improved crystallization ability of the polymer. Notably, the addition of the spherical Al₂O₃ also significantly enhanced the melt flow rate of the composites, and improved its processing performance.