Do-it-yourself functionalized silicones part 2: synthesis by ring opening polymerization of commercial cyclosiloxanes

The second paper of the series devoted to the preparation and characterization of vinyl and hydrido-functionalized silicones proposes readily available techniques to polymerize commercially available cyclosiloxanes. This study is divided into two main sections: one relies on the synthesis of various functional silicone oils by heterogeneous cationic ring opening polymerization (ROP) of cyclotetrasiloxanes (D-4, D-4(H)) and appropriate 1,3-difunctional disiloxanes; the second part describes the anionic ROP of hexamethylcyclotrisiloxane (D-3) initiated by potassium silanolates to prepare both homo- and hetero-vinyl functionalized silicones. The conditzions in which polymers with desired molecular weights can be obtained have been established and some kinetic considerations are also reported. The width of the final molar mass distribution ranged between 1.5 and 1.8, respectively, in any case narrower than the mixtures proposed by different providers (around 2). Polymers were characterized by different techniques of size exclusion chromatography (SEC), proton and silicon nuclear magnetic resonance (H-1 and Si-29 NMR), and mass spectrometry. Copyright (C) 2009 John Wiley & Sons, Ltd.