In order to study the performance changes of silicone rubber and fluorinated silicone rubber after freezing at extremely cold temperature, the two materials were put into a low-temperature test box to freeze for 0, 150, 300, 450, 600, 750, 900, 1 050 h, and the temperature was set as -50℃. After freezing, the samples were taken out and stood for 2 hours at room temperature, and then the changes of breakdown voltage, maximum tensile force, tensile strength, hardness, and surface topography of the materials with freezing time were measured, and the principle were analyzed. The results show that with the increase of the low temperature freezing time, the breakdown voltage, maximum tensile force, and tensile strength of silicone rubber and fluorinated silicone rubber increase, while the hardness is almost constant. There are cracks on the sample surface after freezing for 300 h, there are obvious cracks and holes after freezing for 750 h, and the crack depth continues to deepen after freezing for 1 050 h. Throughout the freezing process in the extremely cold environment, the performance of fluorinated silicone rubber is better than that of silicone rubber, which indicates that the performance of fluorinated silicone rubber is more stable than that of silicone rubber in extremely cold environment.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |