In order to study the effects of pressure and temperature on the conductivity of ethylene propylene rubber (EPDM) insulation for cables, the polarization current of EPDM under different electric field, temperature, and pressure were measured. The polarization index and conductivity were extracted, and the change law of the performance of EPDM was analyzed. The effect of pressure and temperature on the conduction mechanism of EPDM on pressure and temperature was studied based on the relationship between quasi-steady-state conductance current density and electric field intensity. The results show that the polarization index and conductivity are linearly related to temperature, but nonlinear related to pressure. This is because the conduction mechanism of EPDM changes under the influence of pressure and temperature, and the increase of temperature can promote the increase of the number of carriers in EPDM. The lower pressure limits the intermolecular movement of EPDM, while the higher pressure can destroy the molecular chain, resulting in an increase in electrical conductivity.
| 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 |