Synthesis of alkyl polymethylsiloxane (APMS) by condensation reaction and study of properties as lubricants

The alkyl polymethylsiloxane (APMS) was prepared by condensation reaction from low hydrogen contenting polymethylsiloxane (l-HPMS) and 1-Chloroalkane, with aluminum chloride as catalysts. In the experiment, the optimum reaction conditions were determined as follows: reaction time 7 h, reaction temperature 150℃, Si-H:C-Cl 1:1.1 and amount of catalyst 4%. The effects of molecular structure on viscosity-temperature characteristics and lubrication performance of APMS were investigated. The viscosity-temperature characteristics reached the optimum with low chain unit ratios and high degree of polymerization. The lubrication performance increased with the increase of the chain unit ratios and degree of polymerization. In addition, effects of the alkyl length were also considered. The viscosity-temperature characteristics decreased, but lubrication performance of APMS increased with the increase of alkyl length.