Preparation of Poly［methyl(3,3,3-trifluoropropyl)siloxane］by Reactive Processing in a Torque Rheometer

Poly［methyl(3,3,3-trifluoropropyl)siloxane］-(PMTFPS) was synthesized in the mixing chamber of a torque rheometer using sodium silanolate as the initiator, dimethyl sulfoxide (DMSO) as the promoter. Effect of the promoter concentration, the reaction temperature and the reaction time on molecular weight and yield of PMTFPS were investigated. The optimum DMSO promoter concentration determined was at 0.017 mol/L, where the numberaverage molecular weight (Mn) of PMTFPS, 2.47×105, with the yield 86.5% was obtained at the optimal reaction temperature (100 ℃) for the optimal reaction time (2.5 min). With the further increase of DMSO concentration and reaction temperature, and the prolongation of reaction time, the molecular weight and yield of PMTFPS were decreased.