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

Summary

• 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:

  $$ - NHC_6 H_5 > - OCOCH_3 > - Cl > - {\rm O}C_2 H_5 > - {\rm O}CH_3 > - {\rm N}(C_2 H_5 )_2 > - {\rm H}.$$