Physical properties and flammability of polyhydroxyamides (PHAs) having poly(ethyleneglycol)methyl ether (MPEG) and/or dimethylphenoxy pendants were studied by using DSC, TGA, FTIR, pyrolysis combustion flow calorimeter(PCFC), and X-ray diffractometer. The degradation temperatures of the polymers were recorded in the ranges of 276~397 ℃ in air. PCFC results showed that the heat release (HR) capacity and total heat release (total HR) values of the PHAs were increased with increasing molecular weight of MPEG. In case of M-PHA 2 annealed at 290 ℃, the values of HR capacity were siginificantly decreased from 253 to 42 J/gK, and 60% weight loss temperatures increased from 408 to 856 ℃ with an annealing temperature. The activation energy for the decomposition reaction of the PHAs showed in the range of 129.3∼235.1 KJ/mol, which increased with increasing conversion. Tensile modulus of PHAs were decreased as increasing chain of MPEG, and showed an increase more than initial modulus after converted to PBOs.

폴리(에틸렌글리콜)메틸에테르[poly(ethyleneglycol)methyl ether, MPEG] 곁사슬기와 짧고 강직한 디메틸페녹시(dimethylphenoxy) 곁사슬기를 갖는 폴리히드록시아미드(poly(hydroxyamide)s, PHAs)의 물성 및 난연특성을 DSC, TGA, FTIR, pyrolysis combustion flow calorimeter(PCFC), X-ray diffractometer를 사용하여 조사하였다. 중합체들의 최대분해온도는 공기 분위기하에서 276∼396 ℃의 범위를 보였다. PHAs의 heat release(HR) capacity와 total heat release(total HR) 값들은 MPEG의 분자량 증가에 따라 증가됨을 보였다. 290 ℃에서 열처리된 M-PHA 2의 경우 열처리 시간에 따라서 HR capacity 값들은 253 J/gK에서 42 J/gK로 감소하였고, 60% 중량 감소 온도는 408 ℃에서 856 ℃로 증가하였다. PHAs의 분해 활성화 에너지는 129.3∼235.1 kJ/mol의 범위를 보이고, 전환율에 따라 증가하였다. PHAs의 인장 모듈러스는 MPEG의 사슬길이가 증가함에 따라 감소하였으며, PBO로 전환된 후에는 초기 모듈러스보다 더 상승하였다.

Keywords: poly(hydroxyamide)s; poly(benzoxazole)s; thermal cyclization reaction; activation energy; heat release rate