紫外光交联低压三元乙丙橡胶电缆绝缘材料配方与性能

Formulation and properties of UV crosslinked low voltage ethylene propylene diene monomer cable insulation material

为了将具有更高效率、更低功耗的紫外光交联技术用于三元乙丙橡胶(EPDM)电缆绝缘层生产,以达到节能减排、高效生产的目标,需研发低固体填料配方体系的EPDM绝缘材料。本文分别通过添加线性低密度聚乙烯(LLDPE)和少量纳米SiO_(2)两种方法对EPDM进行补强。设计了可光交联的EPDM绝缘材料配方,并系统研究了紫外光交联EPDM材料的力学性能、交联性能、电学性能。结果表明,随着辐照时间的延长,EPDM力学性能明显下降,交联度迅速上升。与EPDM相比,LLDPE/EPDM材料交联程度和力学性能明显升高,当LLDPE含量为10wt%时,LLDPE/EPDM材料断裂伸长率为539%,拉伸强度为12 MPa,邵氏硬度为80 A,可以满足使用要求。对于SiO_(2)/EPDM材料,当SiO_(2)含量为4%(与橡胶的质量比,下同)时,力学性能最优,断裂伸长率为596%,拉伸强度为14 MPa。与EPDM相比,SiO_(2)/EPDM复合材料的硬度变化不大,但交联程度降低,当辐照时间为12 s时,延伸率为40%,但仍可满足使用要求。添加0.5%抗氧剂1010可以抑制材料辐照交联过程中的降解,复合材料的力学性能大幅度提升,同时可以为EPDM绝缘材料提供较好的耐热老化性能。两种适用于紫外光交联技术的EPDM电缆绝缘材料均可满足电缆绝缘使用要求。其中,LLDPE补强材料的交联度和电学性能更优,但是对材料的硬度影响较大,而SiO_(2)对复合材料的硬度几乎没有影响,但是交联度与电学性能略有下降。

In order to employ the high-efficiency,low-power-consumption ultraviolet light technology for the crosslinking of the ethylene propylene diene monomer(EPDM)rubber cable insulation layer and achieve the goal of energy conservation,pollution reduction and efficient production,it is necessary to develop EPDM insulation formulation with low content of solid fillers.In this paper,EPDM was reinforced by adding linear low density polyethylene(LLDPE)and a small amount of nano SiO_(2).The formula of photo crosslinkable EPDM insulating material was designed,and the mechanical,crosslinking and electrical properties of UV crosslinked EPDM were systematically studied.The results show that,with the irradiation time increasing,the mechanical properties of EPDM are significantly decreased,and the crosslinking degree is rapidly increased.Compared with EPDM,the crosslinking degree and mechanical properties of LLDPE/EPDM materials are significantly higher.When the LLDPE content is 10wt%,the elongation at break of the LLDPE/EPDM material is 539%,the tensile strength is 12 MPa,and the Shore hardness is 80 A,which can meet the requirements of use.For SiO_(2)/EPDM composite,when the SiO_(2) content is 4%(mass ratio to rubber),the mechanical properties are the best,the elongation at break is 596%and the tensile strength is 14 MPa.Compared with EPDM,the hardness of SiO_(2)/EPDM composite is almost unchanged,but the crosslinking degree is reduced.When the irradiation time is 12 s,the loading elongation of SiO_(2)/EPDM is 40%,which still meets the requirements of use.The degradation of the material during irradiation can be suppressed after 0.5%mass ratio of Irganox1010 is added,and the mechanical properties of the composite material are improved.Moreover,Irganox1010 can improve the thermo-oxidative aging resistance of the composite.Both two kinds of modified EPDM composites which are designed for UV cross-linking technology can meet the requirements of cable insulation.The blending of LLDPE increases the crosslinking degree and electrical properties of the material,but bring the negative impact on the hardness of EPAM,while the doping of SiO_(2) has almost no effect on the hardness of the composite,but the crosslinking degree and electrical properties are slightly weakened.