Page 245 - Handbook of Plastics Technologies

ELASTOMERS

ELASTOMERS 4.37

SCHEME 4

SCHEME 5

SCHEME 6

SCHEME 7

4.5.1.6 Effects of Changes in Curing System on Vulcanizate Properties. Increases in
sulfur and accelerator concentrations give higher cross-link densities and, therefore,
higher moduli, stiffness, hardness, and so on. However, as the ratio of the concentration of
accelerator to the concentration of sulfur increases, the proportion of monosulfidic cross-
links increases in natural rubber compounds. Greater amounts of accelerator (with respect
to sulfur) also give an abundance of pendent groups of the type, -S -Ac, attached to and
x

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