Historical Aspects of Poly dimethysiloxane

The search for organosilicon polymers in general and poly(dimethylsiloxane) in particular has its origins in attempts to bridge the gap between mineral silicates, on the one hand, and organic polymers on the other. The need for flexible substances that can serve as high- 

The discovery of poly(dimethylsiloxane) and the foundation of the silicones industry has been the subject of many reviews and for the full details of this interesting historical account the reader is directed to these appropriate sources [5, 7]. A brief summary of this is presented here. 

The development of the silicones industry depended very critically on the ability to make compounds containing Si-C bonds. From the point of view of commercial viability it was also important that organosilicon compounds should be prepared by efficient synthetic methodologies which would contain a minimum number of sjmthetic steps and which avoid expensive reagents. The achievement of these goals culminated in the current silicone technology. 

The first efforts of making organosilicon compounds are due to Friedel and Crafts in the nineteenth century. They alkylated silicon tetrachloride with the help of zinc alkyls or mercury alkyls. Silicon tetrachloride is prepared by the chlorination of silicon and the latter itself is produced by the Moissan method of high temperature reduction of Si02 with carbon which involves reduction in an electric furnace by the use of graphite electrodes. The whole process can be summarized as follows (see Eq. 6.1) [5, 7]. 

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