초록 |
Hydroxyl polyimides were prepared via thermal imidazation from 6FDA and bisAPAF, and converted to polybenzoxazole (PBO) at various temperatures and times. Percentage conversions of each PBO were derived by analyzing TGA and ATR-FTIR. Furthermore, several properties of two PBO, treated at 400 oC for 5hs and at 450 oC for 1hr for full conversion, were compared in mechanical properties by universal testing machine and in gas permeability by time-lag method. This study suggests that treatment at 450 oC for 1hr undergo degradation due to over-heating at high temperature. |