Polyhydroxyamides (PHAs) having poly(ethylene glycol)methyl ether (MPEG) and/or dimethylphenoxy pendant groups were synthesized by solution polycondensation at low temperature. The inherent viscosities of the PHAs measured at 35 ℃ in DMAC or DMAc/LiCl solution were in the range of 0.51~2.31 dL/g. This precursor polymers were studied by FT-IR, 1H-NMR, DSC, and TGA. Solubility of the precursors with higher MPEG unit was increased, especially the polymer having MPEG (Mn=1100) was soluble or partially soluble in ethanol, methanol, and water as well as aprotic solvents, but the PBOs were nearly insoluble in a variety of solvents. PHAs were converted to polybenzoxazoles (PBOs) by thermal cyclization reaction with heat of endotherm. In case of the precursors having MPEG unit, the precursor polymers with a higher Mn were fully cyclized at a lower temperature than one with a lower Mn.

Poly(ethylene glycol)methyl ether(MPEG)와 dimethylphenoxy 팬던트 그룹을 갖는 polybenzoxazoles(PBOs)의 중합 전구체인 poly(o-hydroxyamides)(PHAs)를 저온 용액 중축합에 의해서 합성하였다. 합성된 중합 전구체들의 고유 점도는 0.51~2.31의 값을 나타내었다. 중합전구체는 FT-IR, 1H-NMR, DSC, 그리고 TGA를 이용하여 특성을 조사하였다. MPEG 단위를 갖는 PHAs는 MPEG의 분자량이 증가할수록 용매특성이 증가하는데, 특히 분자량이 1100인 MPEG를 갖는 PHA의 경우 aprotic 용매뿐만 아니라 에탄올, 메탄올, H2O에도 용해되었으나, 열적 고리화 반응에 의해 PBOs로 전환되면 어떠한 용매에도 용해되지 않았다. 그리고 MPEG 만을 갖는 중합 전구체인 경우, MPEG의 분자량이 증가 할수록 고리화 반응온도는 감소함을 확인할 수 있었다.

Keywords: polyhydroxyamides; polybenzoxazoles; thermal cyclization reaction