笼型聚倍半硅氧烷增韧3层聚酰亚胺薄膜的制备与性能

以3,3′,4,4′-联苯四酸二酐(BPDA)-对苯二胺(PDA)/4,4′-二苯醚二胺(ODA)型聚酰亚胺为芯层,将2,2′-双(4-(4-氨基苯氧基)苯基)丙烷(BAPP)-BPDA型聚酰胺酸涂覆于芯层的上、下表面并热亚胺化得到3层聚酰亚胺薄膜。为提高3层聚酰亚胺薄膜的韧性,将降冰片烯二酸酐-马来酰亚胺基七异丁基聚倍半硅氧烷交替共聚物(poly(MIPOSS-alt-NA))作为BPDA的共单体引入到上、下表层的热塑性聚酰亚胺中。结果表明,当poly(MIPOSS-alt-NA)的质量分数为6.0%时,3层聚酰亚胺薄膜的断裂伸长率从7.2%提高到14.5%,热膨胀系数则从27.0×10-6 K-1降低至23.6×10-6 K-1,与铜箔制备的柔性覆铜板剥离强度达到12.0 N/cm,针对拉伸断面电镜照片的变化对增韧机理进行了分析。

Preparation and Properties of Three-Layer Polyimide Films Toughened by Polyhedral Oligomeric Silsesquioxane

A series of three-layer polyimide films with sandwich-like structure were prepared by coating polyamic acid onto both sides of middle-layer polyimide and further thermal imidization.The middle-layer polyimide came from the condensation of 3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA)and p-phenylenediamine(PDA)/4,4′-oxydianiline(ODA),and the top and bottom layers were the thermoplastic polyimide made from the polymerization of BPDA and 2,2′-bis4-(4-aminophenoxy)phenyl]propan(BAPP).In order to improve the toughness of three-layer polyimide films,poly(MIPOSS-alt-NA)was introduced into the top and bottom layers.It is found that the elongation at break of the three-layer polyimide film increases from 7.2%to 14.5%and the coefficient of thermal expansion(CTE)decreases from 27.0×10-6 K-1 to 23.6×10-6 K-1 with 6.0%poly(MIPOSS-alt-NA).Furthermore,the peel strength of flexible copper clad laminate(FCCL)made with the three-layer polyimide film achieves 12.0 N/cm.The toughening mechanism was investigated by SEM micrographs of tensile-fractured surface.