초록
Organocyclosiloxane oligomer[$(R_2SiO)_n$, n=2, 3, 4, 5]와 dimethyldichlorosilane을 Pyridine N-oxide 촉매 존재하에서 개환 반응시켜 linear chlorine terminated siloxane(yields;71.2~86.5%)를 얻었다. $0^{\circ}C$에서 linear chlorine terminated siloxane과 dimethylamine을 반응시켜 amino terminated siloxane oligomer(yields;76.2~85.3%)를 얻은 후 이 화합물들과 1,4-bis(dimethylhydroxysilyl)benzene을 반응시켜 공중합체들(yields;58.0~71.0%)을 합성하였다. 이들 공중합체의 구조는 FT-IR 및 $^1H$-NMR로 확인하였으며, DSC 및 TGA thermogram을 통하여 이들 중합체들의 열적특성을 조사하였다. TGA thermogram으로부터 polymer I (n=2)의 초기분해온도는 $476^{\circ}C$로 가장 낮았고, polymer IV(n=5)가 $485^{\circ}C$로 가장 높았다. n의 수가 증가할수록 열안정성은 다소 우수한 것으로 관찰되었고, DSC thermogram에서 중합체들의 유리전이온도는 polymr IV (n=5)가 $-76^{\circ}C$로 가장 낮았으며, n의 수가 감소할수록 높게 나타났음을 알 수 있었다.
Low molecular weight linear chlorine terminated siloxanes (yields;71.2~86.5%) were prepared by reactions of cyclotri-, cyclotetra- and cyclopentasiloxane with dimethyldichlorosilane in the presence of pyridine N-oxide catalyst. The amine terminated siloxane oligomers were obtained in good yields(76.2~85.3%) by the reaction of linear chlorine terminated siloxanes with dimethylamine at $0^{\circ}C$. In this investigation, we have studied on the syntheses and properties of copolymers (yields;58.0~71.0%) obtained from the reaction of amine terminated siloxane oligomers with 1,4-bis(dimethylhydroxysilyl)benzene. The structures and properties of the copolymers were examined by FT-IR, $^1H$-NMR, TGA and DSC. Initial degradation temperatures($T_D{^i}$) of the polymer I and IV were confirmed as 476 and $485^{\circ}C$, respectively. The thermal stabilities of the polymers were found to be increased with increasing n of $(R_2SiO)_n$. The glass transition temperatures(Tg) of the polymers were increased with decreasing n of $(R_2SiO)_n$, and the lowest Tg revealed $-76^{\circ}C$ when n=5.
