In order to study the performance variation characteristics of silicone rubber and fluorinated silicone rubber at extremely cold temperatures, two type samples were frozen for 0, 150, 300, 450, 600, 750, 900 and 1050 h in a low-temperature test chamber with a constant temperature of -50 °C. After the samples reached a certain freezing time, they were taken out and placed at room temperature for 2 h, then the breakdown voltage, mechanical tensile properties, and hardness and surface morphology were measured, and the mechanism was analyzed. The breakdown voltage, maximum tensile force, and tensile strength of the two type samples increased with freezing time. The elongation at break decreased with freezing time, but the hardness of the two materials changed little. Microcracks appeared on the surface of the samples at about 300 h and some tiny pore and holes appeared at 750 h. The length and depth of the microcracks gradually developed with freezing time. The comparative test results of the two materials showed that the performance of fluorinated silicone rubber was better than that of silicone rubber, which indicates that fluorinated silicone rubber is more stable for some applications in extremely cold environments.
Keywords: electrical performance; extremely cold environment; fluorinated silicone rubber; mechanical performance; silicone rubber.