Synthesis and ionic conductivity of siloxane based polymer electrolytes with pendant propyl acetoacetate groups

Abstract

Abstract Hydrosilylation reaction of 2.4.6.8-tetrahydro-2.4.6.8-tetramethylcyclotetrasiloxane (D4 H) with allyl acetoacetate at 1:4.1 molar ratios of initial compounds in the presence of platinum hydrochloric acid (0.1 M solution in THF), Karstedt’s catalyst (Pt2[(VinSiMe2)2O]3) and platinum on the carbon have been carried out and D4 R type compounds obtained. Reaction order, rate constants and activation energies for hydrosilylation reactions in the presence of Karstedt’s catalyst have been determined. Ring-opening polymerization reaction of D4 R in the presence of catalytic amounts of powder-like potassium hydroxide has been carried out. A linear methylsiloxane oligomer with regular arrangement of propyl acetoacetate groups in the side chain has been obtained. The synthesized methylorganocyclotetrasiloxane and oligomers were studied by FTIR, 1H, 13C and 29Si NMR spectroscopy. Comb-type oligomers were characterized by gel-permeation chromatography, wide-angle X-ray diffractometry and differential scanning calorimetry. Solid oligomer electrolyte membranes have been obtained via sol–gel processes involving lithium trifluoromethylsulfonate (triflate) or lithium bis(trifluoromethylsulfonyl)imide. The specific volumetric electrical conductivity of the membranes at room temperature covers a wide range, from 10−10 to 10−4 S · cm−1, and depends on the structures of grafted anion receptors and the polymer backbones. Higher values of the specific conductivity are seen for the membranes containing triflate.