Trisyl Modification of Epoxy- and Chloromethyl-polysiloxanes

The new bulky organosilicon compound HC(Me2SiCH2CH2CH2OCH2CycloCHCH2O)3 was synthesized by hydrosilylation of tris(dimethylsilyl)methane (HMe2Si)3CH and allyl glycidyl ether (AGE) in the presence of H2PtCl6 as a catalyst. Polysiloxanes containing 3-(2,3-epoxypropoxy)propyl and chloromethylphenethyl groups were synthesized by hydrosilylation of AGE and chloromethyl styrene (CMS) with hydrogen-containing polymethylsiloxane (PMHS). Both types of polymers could be modified by incorporation of the highly sterically-demanding tris(trimethylsilyl)methyl [trisyl = (Me3Si)3C] substituent. The trisyl (Tsi) groups were attached to the obtained polymers as side chains by reacting excess trisyl lithium with benzyl chloride and epoxy groups. The epoxy groups possess a higher reactivity for TsiLi than the chloromethyl groups. The ring opening reaction between the epoxy groups and TsiLi is fast. The modification increases the rigidity of the polymers as shown by differential scanning calorimetry analysis. The incorporation of the Tsi groups into the polymer structure creates macromolecules of novel architecture with potential use as membranes for fluid separation. All the resulting polymers were characterized by FT-IR and 1H NMR spectroscopy