Synthesis and investigation of the properties of liquid polydimethylsiloxanes containing ester and ether groupings in the methyl groups

Abstract

1. New organosilicon liquid linear polymers of structure $$(CH_3 )_3 SiO\left| {\begin{array}{*{20}c} - \\ { - - } \\ - \\ \end{array} } \right.\begin{array}{*{20}c} {CH_3 } \\ | \\ {Si} \\ {|CH_3 X} \\ \end{array} - O\left. {\begin{array}{*{20}c} - \\ { - - } \\ - \\ \end{array} } \right|_n Si(CH_3 )_3 ,$$ in which X=OCH3, OC2H5, and OCOCH3 and the degree of polymerization n had various values, were synthesized, and their principal properties were studied. 2. The temperature-dependence of the viscosities of the compounds obtained was investigated, and it was shown that the dependence is more marked in compounds containing acetoxy in the methyl side groups. 3. The activation energy for viscous flow of the compounds investigated in the temperature range 0°–100° depends on the nature of the polar group present. With respect to their effects on the intensity of intermolecular action in compounds of structure $$(CH_3 )_3 SiO\left| {\begin{array}{*{20}c} - \\ { - - } \\ - \\ \end{array} } \right.\begin{array}{*{20}c} {CH_3 } \\ | \\ {SiO} \\ {|CH_2 X} \\ \end{array} \left. {\begin{array}{*{20}c} - \\ { - - - } \\ - \\ \end{array} } \right|_n Si(CH_3 )_3 ,$$ the investigated groups may be arranged in the following order: $$ - NHC_6 H_5 > - OCOCH_3 > - Cl > - {\rm O}C_2 H_5 > - {\rm O}CH_3 > - {\rm N}(C_2 H_5 )_2 > - {\rm H}.$$