주사슬에 디이미드 고리를 갖는 새로운 방향족 Poly(hydroxyamide)s의 합성 및 열적 성질

Abstract

Fully aromatic polyhydroxyamides(PHAs) having Diimide ring in the Main chain were synthesized by direct polymerization method. PHAs were studied by FT-IR and 1H-NMR. The thermal properties of the polymers were also studied by using DSC and TGA. The inherent viscosities of the PHAs measured at 35 → in DMAc solution were in the range of 0.54∥1.58 dL/g. Upon investigation about each of solubilities of the polymers, it was confirmed that all of the synthesized PHAs were soluble in DMF, DMSO, NMP, DMAc, and etc. as well-known aprotic solvents. In particular, PHA 5―8 containing CF group in the main chain were more readily soluble in pyridine and TFA; however, the PBOs were almost insoluble in a variety of solvents. It was confirmed by using DSC that PHAs were fully converted to polybenzoxazole(PBOs) by thermal cyclization reaction, and their endothermic peak by thermal cyclization was observed in the range of 270―304 →. PBO 1 and 5 of all the synthesized PBOs also had Tg at 246 → and 258 → each. The thermal properties of the polymers, the synthesized PHAs and PBOs, were studied by using TGA. As a result, PHA 1―4 including benzidine in the main chain have the Td,max around 605―619 →. PHA 5―8 having CF group also resulted in the Td,max around 559―567 →, which assumed that the weight loss occurred more in accordance with an arising from degradation of the bulky CF group at hight temperature. PBO 1―4 containing benzidine group showed the Td,max around 606―626 →, and PBO 4 including pyridine ring appeared at the highest temperature, 626 →. However, PBO 5―8 having CF group had the Td,max around 559―567 →. In turn, the Td,max of PBO 5―8 was lower than that of PBO 1―4.