Polypropylene (PP) insulation is an important development direction of environmentally friendly recyclable cable insulation materials. However, isotactic PP insulation suffers from issues such as high low-temperature modulus, poor toughness, and low elongation at break. Although the introduction of elastomers into PP insulation through blending or copolymerization methods can optimize its mechanical properties, it also leads to a severe decline in insulation performance. For this purpose, this paper reviewed the research progress on strengthening the performance of cable insulation based on chemical grafting modification. At first, we comparatively analyzed the influence patterns and mechanisms of three types of grafting monomers—polar small molecules, high-energy electron/photon-trapping small molecules, and free radical scavenging small molecules—on the dielectric properties of cable insulation, including space charge accumulation, breakdown, and electrical tree degradation, and proposed the optimal method for chemical grafting monomers. Then different grafting modification methods such as solution grafting, melt grafting, solid-phase grafting, suspension grafting, and radiation grafting were compared and analyzed. At last, the problems in the current chemical grafting modification methods for PP cable insulation were summarized, and the development and application of chemical grafting modified PP cable insulation materials were prospected.
| 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 |