Preparation of branched, ladder and cyclolinear polyorganosiloxanes

In the process of vulcanisation in air Elastosils form rubberlike materials and have good adhesion to steel, copper, aluminum, wood, ceramics, concrete, polymethylmetaciylate, glass and other materials. Consequently, they do not require the use of any special sublayer. Optimal physicochemical properties of Elastosils are achieved after 5-7 days of solidification at 60-75% humidity in air. The main properties of glue sealants Elastosil are given in Table 24. 

The properties of branched and ladder polyorganosiloxanes are determined by two factors the functionality of parent monomers, determined by 

If the functional groups are used completely, the products are mostly cross-linked, nonmeltable and insoluble however, with the same R Si ratio special techniques for the treatment of original organochlorosilanes can create ladder structures and help to prepare flexible high-melting or non-mentable, but soluble, products. 

The introduction of difunctional elements (dimethylsiloxy, diethylsiloxy or methylphenylsiloxy elements) into the main chain of the polymer forms relatively elastic polymers, mainly cyclolinear  

as the R Si ratio increases and the number of cross links decreases, polymers can range from glasslike to rubbery. Most cyclolinear and branched polymers are obtained when the R Si ratio is from 1 1 to 1.6 1. 

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