Mineral sources of polyorganosiloxane materials

✍ Scribed by Atwal, Rajinder S. ;Bicknell, Stanley ;Cook, Colin B. ;Currell, Brian R. ;Midgley, Henry G. ;Mooney, Anthony J. ;Parsonage, John R.

• Book ID: 104527068
• Publisher: Wiley (John Wiley & Sons)
• Year: 1979
• Tongue: English
• Weight: 470 KB
• Volume: 11
• Category: Article
• ISSN: 0007-1641
• DOI: 10.1002/pi.4980110410

✦ Synopsis

Abstract

The trimethylsilylation of biotite and phlogopite gives good yields of polyorganosiloxanes. Al^3+^ ions have an important influence on the fragmentation of the mineral structure into silicate anions prior to trimethylsilylation.

The authors have shown by using wet analytical techniques as well as X‐ray diffraction and electron probe microanalysis that biotite and phlogopite retain aluminium in preference to magnesium during the course of extensive trimethylsilylation reactions. The labile nature of the >Al‐O‐Si<‐ bonds, and the size of the AI^3+^ ion which allows exchange between the octahedral and tetrahedral mineral sites, contribute to the good yields of polyorganosiloxanes which can be produced by this method. The mechanism for the reaction is presented. Yields may be increased by decreasing the particle size of the mineral and also by removing polyorganosiloxanes from the mineral surface.