Novel monomer for polybenzimidazole was prepared and polymerized via aromatic nucleophilic substitution reaction. Thus, N-(4-fluorobenzoyl)-4-methoxy-N'-naphthyl-1,2-phenylenediamine was synthesized from the reaction of 4-methoxy-Nnaphthyl-1,2-phenylenediamine and 4-fluorobenzoyl chloride. N-(4-fluorobenzoyl)-4-methoxy-N'-naphthyl-1,2-phenylenediamine was converted to 2-(4-fluorobenzoyl)-5-hydroxy-1-naphthylbenzimidazole by ring closure and demethylation reaction. Polymerization was done in N-cyclohexyl-2-pyrrolidinone (CHP) containing potassium carbonate. The resulting polymer was soluble in N-methyl-2-pyrrolidinone (NMP) and had inherent viscosity of 0.38 dL/g (NMP at 30 ℃). The glass transition temperature (Tg) of the polybenzimidazole was 270 ℃. The thermogravimetric analysis (TGA) thermograms of this polymer showed 5% weight losses at 550 ℃ in nitrogen and at 540 ℃ in air.

나프탈렌을 측쇄로 갖는 새로운 폴리벤즈이미다졸 단량체을 합성하고, 이 단량체를 친핵치환반응에 의해 중합하였다. 4-Methoxy-N-naphthyl-1,2-phenylenediamine과 4-fluorobenzoyl chloride의 반응으로 N-(4-fluorobenzoyl)-4-methoxy-N'-naphthyl-1,2-phenylenediamine이 합성되었고 이로부터 고리화반응 및 demethylation에 의해 단량체인 2-(4-fluorobenzoyl)-5-hydroxy-1-naphthylbenzimidazole이 얻어졌다. 중합반응은 potassium carbonate를 함유하는 N-cyclohexyl-2-pyrrolidinone (CHP)에서 행해졌다. 생성된 폴리벤즈이미다졸은 N-methyl-2-pyrrolidinone (NMP)에 용해되었고 0.38 dL/g (NMP at 30 ℃)의 대수 점도를 가졌다. 유리전이온도(Tg)는 270 ℃였고 열중량분석에서 5% 중량감소를 보이는 온도는 질소분위기에서는 550 ℃, 공기중에서는 540 ℃였다.

Keywords: polybenzimidazole; aromatic nucleophilic substitution reaction; heat resistant polymers