불소화 Poly(hydroxyamide)s의 제조 및 특성

Abstract

A series of fully aromatic poly(hydroxyamide)s(PHAs) were synthesized by direct polycondensaton of diacides containing di-ether, di-imide ring and trifluoromethyl group with 3,3′-dihydroxybenzidine. PHAs were studied by FT-IR, 1H-NMR, DSC, XRD and TGA. PHAs exhibited inherent viscosities in the range of 0.62∼0.88 dL/g at 35 ℃ in DMAc solution. The solubility revealed that PHAs were readily soluble in Pyridine, THF and aprotic solvents such as DMAc, DMF, DMSO and NMP. PBO 2 and PBO 4 were soluble in sulfuric acid with LiCl(on heating). While, PBO 1 and PBO 3 were quite insoluble in other solvents except partially soluble in sulfuric acid. It was confirmed by using DSC that PHAs were fully converted to PBOs via a thermal cyclization reaction, whose endothemic peaks were observed in the temperature range of 277 ℃∼293 ℃. Thermal properties of PHAs and PBOs were characterized by TGA. For PHAs, the first 10% of weight losses were occurred in the temperature of 346 ℃∼526 ℃, and then the maximum weight losses were followed in the temperature range of 675 ℃∼683 ℃. However, for PBOs, the first once were noticed in the temperature range from 540 ℃∼575 ℃, and the maximum losses were successively observed in the temperature range of 672 ℃∼681 ℃. Here, the char yields were 49%∼55% for PHAs, and 51%∼59% for PBOs, respectively.