硅脂对电缆中间接头硅橡胶力学特性的影响

Effect of Silicone Grease on Mechanical Properties of Silicone Rubber for Cable Intermediate Joint

在安装电缆附件时,通常会在电缆附件硅橡胶绝缘和电缆本体交联聚乙烯绝缘之间的界面处涂覆硅脂,硅橡胶吸收硅脂后会对其力学特性产生影响。目前关于硅橡胶在多种情况下吸收硅脂后其力学的研究并不充分。该文研究了吸收硅脂后对其基本力学性能的影响,系统研究了扩张程度、温度和吸收率对硅橡胶吸收硅脂后应力松弛和蠕变及永久变形率的影响,并研究了不同涂覆条件对裂痕发展的影响。结果表明:硅橡胶吸收硅脂后弹性模量、拉伸强度和断裂伸长率均减小;硅橡胶吸收硅脂后的应力松弛与扩张程度和温度之间无明显规律,但其永久变形率随扩张程度的增加而增加;硅橡胶吸收硅脂含量越大,产生的应力松弛和蠕变及永久变形率越严重;仅裂痕处涂覆硅脂时,裂痕发展最为迅速。

When installing cable accessories,silicone grease is usually applied at the interface between silicone rubber insulation of cable accessories and XLPE insulation of cable body.The mechanical properties of silicone rubber will be affected after silicone rubber absorbs silicone grease.At present,the mechanics of silicone rubber after absorbing silicone grease in many cases is not adequately researched.In this paper,the influence of absorbing silicone grease on its basic mechanical properties was studied,the influences of expansion degree,temperature,and absorptivity on the stress relaxation,creep and permanent deformation rate of silicone rubber after absorbing silicone grease were systematically studied,and the influence of different coating conditions on crack development was studied.The results show that the elastic modulus,tensile strength,and elongation at break of silicone rubber decrease after absorbing silicone grease;there is no obvious rule between the stress relaxation and expansion degree and temperature,but the permanent deformation rate increases with the increase of expansion degree;the greater the content of silicone rubber absorbed silicone grease is,the more serious the stress relaxation,creep and permanent deformation rate are.When the silicone grease is only applied at the crack,the cracks develop most rapidly.