Dong Yinjie, Wang Zhaoyang, Huo Shouchao, Lin Jun, He Shaojian
State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China.
Polymers (Basel). 2022 Jan 19;14(3):385. doi: 10.3390/polym14030385.
Breakdown strength is an important parameter for polymer dielectric, and introducing inorganic filler into the polymer matrix is an efficient method to improve the breakdown strength. In this work, graphitic carbon nitride nanosheets (CNNS) were ultrasonically exfoliated and coated with polydopamine to obtain modified nanosheets (DCNNS), and then polyimide (PI) composite films with various CNNS and DCNNS were prepared and compared. Owing to the abundant hydroxyl groups of polydopamine, good filler-polymer compatibility and uniform filler dispersion were achieved for PI/DCNNS composites. Both breakdown strength and dielectric constant were improved with the addition of either CNNS or DCNNS. However, at the same filler content, the PI/DCNNS composites exhibited higher breakdown strength and dielectric constant than the PI/CNNS. The PI composite with 0.5 wt% DCNNS showed the highest breakdown strength of ~300 kV/mm, increased by 67.6% as compared to the pure PI, while the PI/CNNS composite with the same filler content only increased by 14.5%.
击穿强度是聚合物电介质的一个重要参数，将无机填料引入聚合物基体是提高击穿强度的有效方法。在本工作中，对石墨相氮化碳纳米片（CNNS）进行超声剥离并用聚多巴胺包覆以获得改性纳米片（DCNNS），然后制备并比较了含有不同CNNS和DCNNS的聚酰亚胺（PI）复合薄膜。由于聚多巴胺含有丰富的羟基，PI/DCNNS复合材料实现了良好的填料 - 聚合物相容性和填料的均匀分散。添加CNNS或DCNNS均提高了击穿强度和介电常数。然而，在相同的填料含量下，PI/DCNNS复合材料比PI/CNNS表现出更高的击穿强度和介电常数。含0.5 wt% DCNNS的PI复合材料表现出最高的击穿强度，约为300 kV/mm，与纯PI相比提高了67.6%，而相同填料含量的PI/CNNS复合材料仅提高了14.5%。
