紫外辐射对绝缘子高温硫化硅橡胶力学性能的影响  

Effects of Ultraviolet Radiation on Mechanical Properties of High Temperature Vulcanized Silicone Rubber

作　　者：李敬敬 李国芳[1] 霍广鹏 张晓东 虞澜[1] LI Jingjing;LI Guofang;HUO Guangpeng;ZHANG Xiaodong;YU Lan(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Faculty of Gemstone and Material,Hebei GE0 University,Shijiazhuang 050031,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]河北地质大学宝石与材料学院,河北石家庄050031

出　　处：《昆明理工大学学报（自然科学版）》2020年第6期29-35,共7页Journal of Kunming University of Science and Technology(Natural Science)

基　　金：国家自然科学基金项目(51462017,51962017)。

摘　　要：采用自行设计的可调式紫外老化试验箱对高温硫化(HTV)硅橡胶试样进行紫外辐射(0 h,250 h,500 h,750 h,1 000 h)加速老化实验,测试辐射前后试样的邵尔A硬度、拉伸强度、拉断伸长率、断口斜角,采用扫描电镜观察断口微观特征,分析紫外辐射致HTV硅橡胶力学性能的变化规律.结果表明:试样残余变形量仅占断裂时伸长量的1.57%~2.87%,随辐射量的增加残余变形量显著减少,硬度略增加,拉伸强度和拉断伸长率降低,断面逐渐平整光滑,断口斜角增大至趋于90°.说明HTV硅橡胶以弹性变形为主,很少量发生塑性变形,源于HTV硅橡胶分子链具有良好的柔性并处于高度卷曲的状态;紫外辐射致HTV硅橡胶硬化变脆,原因是紫外线切断了HTV硅橡胶分子链中能量较低的部分Si-C、C-C键,形成的自由基~Si·发生进一步的交联反应,降低了HTV硅橡胶的韧性.Aging tests by 320~750 nm radiation(0 h,250 h,500 h,750 h,1 000 h) were carried out on the samples of high temperature vulcanized(HTV) silicon rubber. The authors tested the Shore A hardness, tensile strength, elongation at break and the fracture angles before and after the radiation, observed the microfeatures of the fracture by scanning electron microscope, and analyzed the mechanical properties of HTV silicone rubber induced by ultraviolet radiation. The results showed that the residual deformation only accounted for 1.57%~2.87% of the elongation at fracture. With the increase of radiation time, the residual deformation reduced significantly, the hardness increased slightly, the tensile strength and extension at break decreased, the section got smoother, the oblique angle of the fracture increased to nearly 90°.This indicates that HTV silicone rubber is characterized by elastic deformation and seldom has plastic deformation, which is due to the good flexibility of HTV silicone rubber molecular chain and its high curl state. Uv radiation causes HTV silicone rubber to harden and become brittle, as ultraviolet rays cut off the Si-C, C-C bond in the molecular chain of HTV silicone rubber, and the free radical Si formed by UV radiation has further cross-linking reaction, which reduce the toughness of HTV silicone rubber.

关 键 词：高温硫化硅橡胶 紫外辐射加速老化 邵尔A硬度 拉伸强度 拉断伸长率 断口特征 

分 类 号：TM215.2[一般工业技术—材料科学与工程]