PDF
Full
Outline
High temperature liquid nuclear magnetic resonance (13CNMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) were used to study three kinds of polypropylene resins for DC capacitors at home and abroad with different temperature resistance grades, and analyze the effect of microstructure on electrical properties. The results show that the isotactic index, intermolecular chain defect distribution, and molecular weight characteristics jointly affect the crystallization characteristics of polypropylene, and thus affect the final high temperature dielectric properties of materials. The isotactic index of 5 units of imported polypropylene resin is greater than 97%, and the intermolecular chain stereodefect distribution is narrow (I=1.075), the weight average molecular weight is higher and the molecular weight distribution index is larger (PDI>5.6), showing excellent high temperature insulation properties (the electric strength α=533 kV/mm). While the molecular weight distribution of domestic polypropylene resin is narrow (PDI<5), the weight average molecular weight is lower, the isotactic index of 5 units is less than 97%, and the intermolecular chain stereodefect distribution is wider (I=1.106), which leads to its poor high temperature insulation performance and low electric strength (α=497 kV/mm).
PDF
159
73
| 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 |
关闭全屏
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
