CAJ | 학술논문

聚酰亚胺薄膜因其优良的电气、机械及热性能已在各种绝缘线缆中得到广泛应用。然而，环境应力可能会造成聚酰亚胺降解，从而降低其绝缘性能。以聚酰亚胺普通薄膜和聚酰亚胺纳米薄膜为测试对象，研究了单层膜、双层膜及三层膜在不同温度下的击穿特性，分析了水分对聚酰亚胺薄膜击穿场强的影响机制。结果表明：普通膜和纳米膜的击穿强度均随试验温度的升高而降低，尤其是当试验温度大于350℃时，下降速率明显增加，其主要原因是由于聚酰亚胺分子在高温下移动并发生热降解。由于单层膜具有更好的散热能力及结构均匀性，因此单层膜具有比双层膜和三层膜更高的击穿场强，纳米膜较高的热导率导致其具有更好的高温稳定性。潮湿环境中的水分子首先通过氢键作用与聚酰亚胺分子上的羧基(C=O)键结合，并进一步与之发生水解反应，使聚酰亚胺薄膜的击穿场强降低。
취선아알박막인기우량적전기、궤계급열성능이재각충절연선람중득도엄범응용。연이，배경응력가능회조성취선아알강해，종이강저기절연성능。이취선아알보통박막화취선아알납미박막위측시대상，연구료단층막、쌍층막급삼층막재불동온도하적격천특성，분석료수분대취선아알박막격천장강적영향궤제。결과표명：보통막화납미막적격천강도균수시험온도적승고이강저，우기시당시험온도대우350℃시，하강속솔명현증가，기주요원인시유우취선아알분자재고온하이동병발생열강해。유우단층막구유경호적산열능력급결구균균성，인차단층막구유비쌍층막화삼층막경고적격천장강，납미막교고적열도솔도치기구유경호적고온은정성。조습배경중적수분자수선통과경건작용여취선아알분자상적최기(C=O)건결합，병진일보여지발생수해반응，사취선아알박막적격천장강강저。
Polyimide (PI) film has been widely applied as electrical insulation for wires and cables due to its excellent electrical, mechanical and thermal properties. However, PI insulation could be degraded because of various environmental stresses, which can cause deterioration of their insulation properties. In this paper, the effects of thermal exposure on dielectric strength of nanocomposite PI film and pure PI film were investigated. The comparison of the breakdown field strength of single layer film, double layer films and three layer films were also studied. The influence mechanism of humidity on the breakdown strength was analyzed. The results show that the breakdown field strength of PI films, both nanocomposite PI film and pure PI film, is greatly decreased with the tested temperature increasing. And the decreasing rate of breakdown field strength increases more obviously when the tested temperature is more than 350℃. It is due to the motion and pyrolysis degradation of PI macromolecules caused by overheating. The single film possesses better heat dissipation potential and homogeneous micro-structure. Therefore the breakdown field strength of single layer film is higher than those of double layer films and three layer films. Higher thermal conductivity of nanocomposite PI film has the better breakdown stability in high temperature environment. Some hydrogen bonds exist between water molecule and carboxyl in the backbone chain of PI polymer. The hydrolysis reaction of PI macromolecule would make the dielectric strength of PI film decrease.