AN INVESTIGATION INTO THE PREPARATION OF POLYORGANOSILOXANE MATERIALS FROM OLIVINE

Modification of the Lentz trimethylsilylation technique was used to synthesize Q(x)M(y) and QxMy(OH)2 polyorganosiloxanes from olivine (Q = SiO4/2, M = (Me3SiO1/2). The products ranged from viscous mobile liquids to hydrophobic insoluble solids with a molecular weight distribution between 3 x 10(3) and 400 x 10(3) depending on the time of addition of silylating agent, hexamethyldisiloxane (MM), to the preformed silicic acids. The stabilisation of the silicic acids leached from olivine was controlled by varying the period of silicic acid condensation-polymerisation reactions and their solution concentration. The absence of the phase transfer agent propan-2-ol from the modified trimethylsilylation reaction resulted in the formation of silica gel. Propan-2-ol, by associating with silicic acids leached from olivine, produced a stable pre-polymer suspension consisting of partially capped silicic acids.