Synthesis and solid-state NMR investigations of radiation-immobilized polysiloxanes on bare, titanium-grafted, and zirconium-grafted silicas

Three different reversed-phase materials for high-performance liquid chroma tography, obtained by sorption of poly(methyloctylsiloxane) (PMOS) onto bar e silica, titanized silica, and zirconized silica pores, followed by immobi lization with gamma -radiation, were characterized by means of solid-state NMR spectroscopy. The surface properties of these stationary phases were in vestigated by Si-29 CP/MAS and C-13 CP/MAS NMR spectroscopy, gamma -Radiati on causes the formation of new bonds, either between PMOS and the different supports or between different siloxane chains, which leads, in either case , to a higher amount of polysiloxane immobilized onto the silica support ma terial.