为提高交联聚乙烯（PEX）的力学性能和热稳定性，以聚乙烯为基体，以硅烷偶联剂（乙烯基三甲氧基硅烷）改性后的蒙脱土为填料，复配制备改性蒙脱土/PEX复合材料，研究不同改性蒙脱土掺量对PEX复合材料力学及热性能的影响。结果表明：掺入质量分数1.0%的改性蒙脱土有效提升了PEX复合材料的拉伸强度、弯曲强度及简支梁冲击强度，提升了PEX复合材料的热稳定性。在此掺量条件下，PEX复合材料的拉伸强度、弯曲强度及简支梁冲击强度分别为16.21 MPa、21.96 MPa和10.31 kJ/m²，电场击穿强度达到最高，为32.21 kV/mm，维卡软化温度为120.91 ℃。因此，适量掺入改性蒙脱土能够有效改善PEX复合材料的力学性能和热稳定性。

In order to improve the mechanical properties and thermal stability of crosslinked polyethylene (PEX), modified montmorillonite/PEX composites were prepared using polyethylene as matrix and silane coupling agent (vinyltrimethoxysilane) modified montmorillonite as filler, and the effect of different modified montmorillonite dosages on the mechanical and thermal properties of the PEX composites were investigated. The results showed that the moderate doping of 1.0% mass fraction modified montmorillonite effectively enhanced the tensile strength, flexural strength and simple beam impact strength of PEX composites, and improved the thermal stability of PEX composites. Under this doping condition, the tensile strength, flexural strength and simply supported beam impact strength of PEX composites were 16.21 MPa, 21.96 MPa and 10.31 kJ/m², respectively, the electric field breakdown strength reached the maximum of 32.21 kV/mm, and the Vicat softening temperature was 120.91 ℃. Therefore, the appropriate amount of modified montmorillonite can effectively improve the mechanical properties and thermal stability of PEX composites.