Preparation and properties of polyimide containing benzoxazole units

Polyimide containing benzoxazole units was synthesized from 2,6-di(p-aminophenyl)benzo-[1,2d;5,4d']-bisoxazole(DAPBBO), 4,4'-diamino diphenylether and 3,3',4,4'-biphenyl tetracarboxylic dianhydride in DMAc. The polyimide films were prepared by casting the solution, followed by thermal imidization reaction. The structure, thermal stability, mechanical and optical properties of the polyimide films were measured. As a result, the introduction of the DAPBBO monomer in the main chains greatly increased the glass transition temperatures and mechanical properties of the polyimide, exhibiting the good ability of UV absorption.