Synthesis of Glucose-Modified Siloxanes by a Simplified Procedure

A simplified alternative for the synthesis of carbohydrate-modified siloxanes is described. The starting siloxane precursors contain glycidyl functional groups, which react with glucose in dimethylformamide (DMF), in the presence of a gel type cation exchanger. The method eliminates protection-deprotection reactions, as well as moisture-sensitive or multiple reaction steps. Glycidyl-functionalized siloxane compounds are commercially available, but can be easily obtained in the desired architecture or chain length by hydrosilylation. Two examples are presented, describing the synthesis of a glucose-modified disiloxane and a siloxane copolymer bearing pendant glucose units. 1H and 13C nuclear magnetic resonance (NMR), and infrared spectroscopy (FT-IR) were used to confirm their structure. Evidence for the preservation of the polysiloxane chain after the reaction was obtained by 1H-NMR, thus confirming the non-invasive role of wet gel-type cation exchanger in chemical modifications of siloxane copolymers. The water-soluble disiloxane compound exhibited typical surfactant behavior, with a critical micelle concentration (CMC) value of 6.3 × 10−4 mol/L (determined by tensiometry) and an equilibrium surface tension of 32.8 mN/m. The obtained copolymer, incompletely modified with glucose, exhibited two glass transition temperatures by Differential Scanning Calorimetry (DSC).