AgNWs@SiO_(2)/PI复合薄膜制备及性能研究

Preparation and Properties of AgNWs@SiO_(2)/PI Composite Films

为了提高聚酰亚胺薄膜热导率的同时维持绝缘性,采用SiO_(2)对AgNWs进行表面绝缘包覆获得AgNWs@SiO_(2)核壳结构,首先通过静电纺丝技术将AgNWs@SiO_(2)分散在聚酰胺酸(PAA)电纺纤维内部,规划导热路径,同时改善AgNWs@SiO_(2)在PI基体中的分散性,再用含AgNWs@SiO_(2)的PAA胶液浸渍PAA电纺膜,热亚胺化后得到E-AgNWs@SiO_(2)/PI复合薄膜。研究其填料改性和含量对复合薄膜导热性能和绝缘性能的影响。结果表明:当填料质量分数为25%时,E-AgNWs/PI和E-AgNWs@SiO_(2)/PI复合薄膜的热导率分别为2.92 W/(m·K)和2.80 W/(m·K),分别是纯PI薄膜的14.6倍和14倍。E-AgNWs@SiO_(2)/PI复合薄膜的介电常数降低至5以下,并且介质损耗因数维持在0.015以下,体积电阻率提升至1.79×10^(13)Ω·m。

In order to improve the thermal conductivity of polyimide film and maintain its insulating properties,SiO_(2) was used to coat AgNWs to obtain AgNWs@SiO_(2) core-shell structure.At First,the AgNWs@SiO_(2) was dispersed in polyamide acid(PAA)discharge fiber by electrospinning technology,and the heat conduction path and the dispersity of AgNWs@SiO_(2) in PI matrix was planned and improved by electrospinning technology,respectively.Then the PAA glue containing AgNWs@SiO_(2) was used to impregnate PAA electrospun film,and an E-AgNWs@SiO_(2)/PI composite film was obtained after thermal imidization.The effects of filler modification and content on the thermal conductivity and insulating properties of the composite films were studied.The results show that when the mass fraction of filler is 25%,the thermal conductivity of E-AgNWs/PI and E-AgNWs@SiO_(2)/PI composite films is 2.92 W/(m·K)and 2.80 W/(m·K),which are 14.6 and 14 times higher than those of pure PI films,respectively.The dielectric constant of E-AgNWs@SiO_(2)/PI composite film decreases to below 5,the dielectric loss factor maintains below 0.015,and the volume resistivity increases to 1.79×10^(13)Ω·m.