Abstract
A diamine, 2,4-diaminophenylethynylbenzene (DAPEB), that have pendant phenylethynyl group, was synthesized. Utilizing DAPEB as one component, a novel soluble polyimide (PI), Solpit-T, that can be thermally cured was synthesized. Solpit-T is soluble prior to curing, but became insoluble in organic solvents after curing, showing improvement in chemical resistance. In addition, cured Solpit-T films revealed large elongation at break; 8% and 39% at 33 mol% and 8 mol% DAPEB in total diamine, respectively, showing that cured Solpit-T has outstanding toughness for thermosetting PI. Cured Solpit-T films have Tg s as high as above 400 °C from the DMA measurement, which is the same as the Solpit-S and PI(PMDA/ODA). Thermogravimetric analyses revealed that 5 % weight loss temperatures were higher than 450 °C.
