Diamine monomer for preparing polyimide film, preparation method and polyimide film

The invention relates to a diamine monomer for preparing a polyimide film, a preparation method and the polyimide film, and belongs to the technical field of high polymer materials and synthesis methods thereof. The diamine monomer is represented by formula (M1); wherein X is selected from arylene of C6-C18, and R is selected from alkyl of C1-5, halogenated alkyl of C1-5, halogen or hydrogen. The diamine monomer can be used for preparing a transparent polyimide film which not only has excellent optical performance, but also is lower in thermal expansion coefficient. 本发明涉及制备聚酰亚胺薄膜用二胺单体及制备方法和聚酰亚胺薄膜，属于高分子材料及其合成方法技术领域。二胺单体由式(M1)表示；其中X选自C6-C18的亚芳基，R选自C1-5的烷基、C1-5的卤代烷基、卤素或氢。使用该二胺单体可制备透明聚酰亚胺薄膜，不仅具有优异的光学性能，且热膨胀系数更低。