Preparation of Monotrimethoxylsilylethyl-Terminated Polysiloxane Fluids and Their Application in Thermal Interface Materials

In this study, α-Trimethylsilylmethyl-ω-dimethylsilyl-terminated polydimethylsiloxane, polydiethylsiloxane and poly[2,2,2-trifluoropropyl(methyl)siloxane] are synthesized using an anion catalyzed nonequilibrium polymerization reaction with trimethylsilylmethyl lithium as the initiator; hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane or 1,3,5-trimethyl-1,3,5-trifluoropropylcyclotrisiloxane as the monomer; and dimethylchlorosilane as an end-capping agent. Three kinds of α-trimethylsilylmethyl-ω-trimethoxylsilylethyl-terminated polysiloxanes are further prepared by hydrosilylation reaction of α-trimethylsilylmethyl-ω-dimethylsilyl-terminated polysiloxanes with vinyltrimethoxysilane using Karstedt’s catalyst. These α-trimethylsilylmethyl-ω-trimethoxylsilylethyl-terminated polysiloxanes are functionalized as in situ surface treatment agents for AlN particles. The effects of the structure of these polysiloxanes on the dispersion of AlN in the polysiloxane matrix and on the heat transfer performance of silicone pastes and silicone rubbers are investigated. A possible mechanism of surface treatment of AlN fillers by these novel silicone fluids is also discussed.