Silicone rubbers classification

The ISO and ASTM DI418 use the following classification for silicone rubbers ... 

For flexible polymers, i.e. those that are able to undergo internal rotation about their backbones, the following classification can be made according to various constraints that we can place on the solidification process (Figure 1.9). There are two other classes of polymer worthy of mention these are rigid rod like molecules where the shape of the polymer has a major effect on its ability to pack, and crosslinked polymers. In the latter system, the morphology of the polymers will be influenced by the size of the chain elements that exist between the network crosslinks. In a polymer system such as a silicone rubber, the... 

As far as nomenclature, there is a standard system for naming the different grades of silicone rubber based on methyl, vinyl, phenyl, and fluorine content in accordance with ASTM D1418. Beyond that, there is no official, generally recognized system of classification for silicone rubber. 

Silicone rubbers may be classified by crosslinking method, viscosity and vulcanisation temperature. Differentiation can be made between hot and cold (room temperature vulcanisation (RTV) rubber types. Within each of these two groups are found single-component and two-component systems, grouped by viscosity range. The viscosity of the rubber (fluid-mouldable, pasty, plastic-firm) determines the processing method and influences the characteristics of the vulcanised material. Figure 7.3 depicts the classification of silicones. 

Uses Crosslinking agent in vulcanization of natural rubber, S/B copolymer, acrylonitrile-butadiene copolymer, ethylene-propylene terpolymers for food-contact articles for repeated use accelerator for food-contact rubber articles for repeated use Regulatory FDA 21CFR 177.2600 Diisostearoyl trimethylolpropane siloxy silicate Classification Silicone polymer... 

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