The vinyl terminated poly(vinyl methyl siloxane) (VPVMS) was synthesized by ring opening polymerization of cyclic vinyl methyl siloxane to investigate the effect of the synthesis conditions on molecular weight, molecular weight distribution, and reaction yield. When the excess capping agent was added and synthesized at a temperature at which activation of the capping agent occurred well, the ring opening reaction equilibrium was quickly achieved, and high yield and low molecular weight were obtained. To synthesize high molecular weight of VPVMS, the reaction temperature needed to be set lower than the activation temperature of end capping agent but it was found that the ring opening reaction equilibrium was slow and the yield was also low. Using minimized end capping agent at 120 ^oC showed the stable ring opening polymerization and it was confirmed that the yield increased as well as the molecular weight. 

환형 비닐 메틸 실록산을 개환 중합에 의하여 vinyl terminated poly(vinyl methyl siloxane)을 합성하여 합성 조건이 분자량, 분자량 분포 그리고 반응 수율에 미치는 영향을 살펴보았다. 과량의 말단 캡핑제를 첨가하고 말단 캡핑제의 활성화가 잘 일어나는 온도로 합성하면 개환반응 평형이 빨리 이루어지며 높은 수율과 낮은 분자량을 얻을 수 있었다. 말단 캡핑제 활성화 온도보다 낮게 반응 온도를 설정하면 상대적으로 높은 분자량을 얻을 수 있으나 개환반응 평형 시간이 늦어지며 수율 또한 낮음을 알 수 있었다. 개환반응이 상대적으로 안정적으로 일어나는 120 ^oC에서 말단 캡핑제 함량을 최소화하면 분자량 증가와 동시에 수율도 함께 개선됨을 확인할 수 있었다.

Keywords: vinyl terminated poly(vinyl methyl siloxane), ring opening polymerization, end capping agent, reaction temperature, reaction time