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聚酰亚胺(polyimide,PI)因其优异的介电特性而应用于高速动车组牵引电机的匝间绝缘中.为了研究等离子体处理对其绝缘性能影响,采用介质阻挡放电(dielectric barrier discharge,DBD)在大气压空气中产生功率密度为24.5W/cm3低温等离子体,并对PI薄膜进行单、双面改性,通过测试接触角、傅里叶红外光谱(Fourier transform infrared spectro-scopy,FTIR)、电晕击穿时间等来研究其性能变化.研究结果表明:随等离子体处理时间的增加,薄膜的接触角逐渐下降,而表面能则逐渐增加,等离子体在薄膜表面引入的—NH2、—COOH、—OH等极性亲水基团是其表面性能改变的主要原因;单层PI薄膜的耐电晕时间随改性时间的增加先增大后减小,且当改性时间为10 s时,其耐电晕时间最大,相对于未改性的PI膜提高了17.7％;双面改性双层叠加PI膜的耐电晕时间相较于未改性的双层叠加PI膜提高了30.3％.研究发现,一定程度的等离子体处理(小于10 s)可在PI膜表面引入极性基团,进而增强其表面电荷扩散能力,增大其表面电荷注入难度,提高单、双层薄膜的耐电晕能力.此外,双层薄膜的耐电晕性能的提高还与层间界面的改善有关.“,”Polyimide(PI) is used in the inter-turn insulation of traction motor for its excellent dielectric properties. In order to study the influence of nonthermal plasma treatment on the insulation property of PI, nonthermal plasma with a power density of 24.5 W/cm3 was gained by dielectric barrier discharge(DBD) in atmospheric pressure air. Single and double sides of PI films were modified, respectively. The contact angle, fourier infrared spectroscopy(FTIR) and corona breakdown time were used to detect the property changes. The results show that the contact angle of PI films decreases with the increase of plasma treatment time, but the surface energy is on the contrary.—NH2,—COOH,—OH and et al. hydrophilic groups introduced on the surface of the films are the main reasons for the surface property changes of PI. Besides, the corona resistance time of single layer PI thin films first increases and then decreases. When the treatment time is 10s, the corona resistance time of PI films is the biggest, and it is 17.7％ increase compared with the unmodified PI films. Meanwhile, the corona resistance time of the double sides modified films is improved by 30.3％ compared with the unmodified bilayer PI films. It is found that a certain degree of plasma treatment(less than 10s) can introduce polar groups on the surface of PI films, thus to enhance the surface charge diffusion ability and increase the difficulty of surface charge injection, which can improve the corona resistance property of single and bilayer films. In addition, the improvement of the corona resistance of the bilayer films is also related to the improvement of the interlayer interface.