Crosslinked polyethylene is a promising polymer regarding its mechanical properties and wear resistance, predominantly used in pipework systems. However, it suffers from low thermal conductivity, which limits its application in geothermal heating/cooling systems. In this work, crosslinked high‐density polyethylene (PEX) composites with spherical graphite (SG) as a reinforcing filler are examined in terms of their thermal and mechanical properties. Thermal conductivity measurements showed a significant improvement of the thermal conductivity of PEX with increasing filler content (40.6% augmentation for 5 wt% SG content), while the experimental data are in good agreement with the Chauhan theoretical model for spherical particles. Tensile tests revealed that the elastic modulus of PEX/SG composites presented a considerable improvement (23.6% augmentation for 5 wt% SG content). Various micromechanical models for the prediction of the composites' elastic behavior were applied to the experimental data, which present a satisfactory agreement with the Takayanagi I two‐phase model for low concentrations of SG, and the Takayanagi II two‐phase model for higher filler content.

中文翻译：

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石墨增强硅烷交联的高密度聚乙烯：填料含量对热和机械性能的影响

就其机械性能和耐磨性而言，交联聚乙烯是一种很有前途的聚合物，主要用于管道系统中。但是，它的导热系数低，这限制了它在地热加热/冷却系统中的应用。在这项工作中，研究了以球形石墨（SG）为增强填料的交联高密度聚乙烯（PEX）复合材料的热和机械性能。热导率测量结果表明，随着填料含量的增加（SG含量为5 wt％时，PEX的热导率增加了40.6％），PEX的热导率有了显着提高，而实验数据与Chauhan球形颗粒理论模型完全吻合。拉伸试验表明，PEX / SG复合材料的弹性模量有相当大的提高（23。SG含量为5 wt％时增加6％。用于预测复合材料弹性性能的各种微力学模型被用于实验数据，这与低浓度SG的Takayanagi I两相模型和填充剂含量较高的Takayanagi II两相模型具有令人满意的一致性。 。