A diisocyanate monomer, thiophenylene-2,5-diisocyanate was synthesized by specific reaction of adipic acid with thionyl chloride and pyridine followed by nucleophilic substitution and Curtius rearrangement.
Polyurethanes containing 2,5-thiophenylene linkage were synthesized by the polycondensation of thiophenylene-2,5,-diisocyanate with various diols in N,N-dimethylformamide at 40-70℃. polymerization yields were 90-100%.
The structures of thiophenylene-2,5-diisocyanate and resulting polymers were identified by IR and $H^1$-NMR spectroscopy. IR spectrum of thiophenylene-2,5-diisocyanate showed chracteristic absorption bands at $3100 cm^{-1}$ (C-H stretching) and $2250 cm^{-1}$ (-N=C=O stretching), those of polyurethanes were observed at $3300-3280 cm^{-1}$ (N-H stretching) and $1750-1710 cm^{-1}$ (carbonyl stretching) region.
The physical properties of these polyurethanes were also investigated. The resulting polyurethanes had inherent viscosities in the range of 0.54-0.33 dl/g. Although most of these polymers were soluble in polar solvents, polyurethanes obtained from aromatic diols were quite insoluble in common organic solvents.
These polyurethanes except for those obtained from aromatic diols revealed relatively good thermal stability. The TGA data showed 5% weight losses of polyurethanes at 252-327℃. The DSC curves showed that these polymers have melting and glass transition temperatures in the range of 120-232℃ and 35-85℃, respectively.
티오페닐렌-2,5-디이소시아네이트는 아디포산과 티오닐 클로라이드와 반응에서 얻어진 생성물에 친핵 치환과 Curtius 재 배열을 함으로서 얻어진다.
2,5-티오페닐렌 결합을 포함하고 있는 폴리우레탄은 티오페닐렌-2,5-디이소시아네트와 여러 디올을 중축합함으로서 만들어진다.
생성된 고분자의 구조는 IR과 $H^1$-NMR분광학에 의해 확인되었으며 물리적인 성질도 조사하였다.
고분자의 고유 점도는 0.54-0.33dl/g의 범위에 있었다. 이들 고분자가 극성 용매에는 대부분 잘 녹았으나 방향족의 디올로부터 만들어진 폴리우레탄은 일반적인 유기용매에 잘 녹지 않았다.
지방족의 디올로부터 만들어진 폴리우레탄은 상대적으로 좋은 열적 안정성을 나타내었다. 열중량 분석 자료는 폴리우레탄의 5% 무게 감소가 252-327℃에서 일어남을 보였다.
또한 이들 고분자의 녹는 점과 글라스 전이 온도는 각각 120-232℃, 35-85℃의 범위에 있었다.
