The basic structure:
Such as nitrile rubber (NBR), styrene-butadiene rubber (SBR), isoprene rubber (IR) and natural rubber (NR) and so a carbon – carbon bonds polymer chains present on the unsaturated bonds in its molecule, but the Silicone Rubber repeating the conversion arrangement of the chain and a silicon atom through an oxygen atom in its main chain is not an unsaturated bond. In terms of the organic polymer, the unsaturated bond is a chemical vulcanization active area, and this area due to effects of ultraviolet radiation, ozone, light and heat degradation.
silicon – oxygen bonds of high bond energy, and the basic structure is completely saturated peroxide cured Silicone Rubber is to maintain the good weather resistance and heat resistance properties of the key. In addition to higher bond energy of the carbon atoms, the silicon atoms have a greater freedom to provide greater space, so that the Silicone Rubber of low glass transition temperature, better air permeability performance. Depending on applications, the advantages of air permeability may also be a disadvantage.
Types of Silicone Rubber:
Side by various functional groups bonded to silicon atoms way classification, Silicone Rubber include: methyl Silicone Rubber (raw material production products), methyl vinyl Silicone Rubber (integrated applications, compression good performance), phenyl methyl vinyl Silicone Rubber (temperature, thermal radiation stability), and trifluoropropyl methyl vinyl Silicone Rubber (chemical synthesis, the temperature range -62-191 ℃). ASTM D-1418 Application abbreviated as:
Q– associated with alternative functional groups of the polymer chains of small Silicone Rubber;
MQ– only silicone elastomers containing methyl-related functional groups in the main chain;
PVMQ– containing phenyl , vinyl, methyl functional groups Silastic;
VMQ– containing vinyl, methyl functional group of the Silicone Rubber;
FVMQ– fluorinated alkyl, vinyl, methyl functional group of the Silicone Rubber;
PMQ– in containing methyl, phenyl functional groups on the main chain of the Silicone Rubber.
ASTMD-2000 in the type and application of abbreviations, the first letter indicates the temperature range, the second letter expressed ASTM 3 oil resistant expansion properties:
FC– high-strength Silicone Rubber;
FE– high strength and high heat resistance of Silicone Rubber;
FK– fluorosilane Silastic;
G– generally used in high temperature Silicone Rubber.
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