a, ω-Vinyl poly (dimethyl-methylphenyl)siloxane prepolymer (VPEPS) was prepared by the equilibrium polymerizationof octamethyl-cyclotetrasiloxane(D_(4)), 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane (D_(3)^(MePh)), and 1,1,3,3,-tetramethyl-1,3-divinyldisiloxane (MVS) as the end-blocker. a, w-hydrogen poly (dimethyl-methylhydrogen)siloxane prepolymer (HPDMS) was also prepared by the equilibrium polymerization of octame-thylcyclotetrasiloxane (D_(4)), 1,3,5-trimethyl cyclotrisiloxane (D_(3)^(MeH)), and 1,1,3,3-tetramethyldisiloxane(MS), The structures of prepared VPMPS and HPMPS, HF`DMS, and catalyst in high speed dissolver, after adding 30 and 40 phr of nanosilica modified with 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane(VMS) based on 100 phr of VPMPS. Modification characteristics of nanosilica filler were measured the content of bound rubber and the time changing of viscosity in LSK. The mechanical properties of LSR nanocomposite were measured by UTM.

Octamethylcyclotetrasiloxane (D₄)과 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane (D₃^(Me,Ph))을 1,1,3,3-tetramethyl-1,3-divinyldisiloxane (MVS)과 평형 중합시켜 실리콘의 Si원자에 dimethyl 및 methylphenyl기가 도입된 α, ω-vinyl poly(dimethyl-methylphenyl) siloxane prepolymer (VPMPS)를 제조하였으며, 또한 D₄와 1,3,5-trimethylcyclotrisiloxane (D₃^(Me,H))을 1,1,3,3-tetramethyldisiloxane (MS)와 평형중합시켜 Si원자에 dimethyl 및 methylhydrogen기가 도입된 α, ω-hydrogen poly (dimethyl-methylhydrogen)siloxane prepolymer (HPDMS)를 제조하였다. 제조한 VPMPS 및 HPDMS의 구조를 FT-IR 및 ^(13)C-NMR을 측정하여 확인하였다. 1,3,5-trivinyl-1,3,5-trimethylcyclotrisilazane (VMS)로 표면처리한 나노 실리카를 VPMPS 100 phr에 대해 30 또는 40 phr와 VPMPS, HPDMS 및 촉매를 고속 교반기로 컴파운딩하여 액상 실리콘 고무(liquid silicone rubber, LSR) 나노 복합체를 제조하였다. 이때 VMS의 사용여부에 따른 액상 실리콘 고무의 bound rubber 함량, 점도변화 및 기계적 특성을 측정하여 비교하였다. VMS를 표면처리제로 처리한 나노 실리카를 사용하여 제조한 액상 실리콘 고무 나노 복합체의 bound rubber 함량이 VMS로 처리하지 않은 나노 실리카를 첨가하여 제조한 액상 실리콘 고무 나노 복합체보다 100% 이상 증가되었으며 시간에 따른 점도변화도 거의 없이 안정한 값을 나타내었다. VMS로 표면처리된 나노 실리카를 보강제로 사용함으로써 인장강도, 인열강도 및 모둘러스가 향상되었다.