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Polyimide (PI) has excellent performance , has very important applications in the high-tech fields . However , most of the polyimide refractory insoluble molding process more difficult , and its application subject to certain restrictions . Therefore developed easy processing polyimide much attention of people. 1,4 - bis ( 4 - amino - phenoxy ) benzene ( TPE -Q ) , 1,3 bis ( 4 - aminophenoxy ) benzene ( TPE- R ) , 2,2 ' - dimethyl - 4,4 '- diaminobiphenyl (m-TB) as a diamine monomer , pyromellitic dianhydride (PMDA) , the dianhydride monomer , using a two-step Preparation of the three polyimide film . In the synthesized polyamic acid stage , with nitrogen protection , when the reaction time is about 3 hours . The imidization temperature is completed by the gradient . FT-IR polyamic acid and polyimide were characterized by peaks were observed polyimide . Compare polyimide solubility in different solvents , and results show that the addition of concentrated sulfuric acid , a polyimide almost insoluble . By thermogravimetric analysis proved film has high thermal stability . The glass transition temperature of the three kinds of films was measured with a differential scanning calorimeter .
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