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Crosslinking Density and the Flory-Huggins Parameter X Applied to EPDM Vulcanizates

One of the most important properties of the polymer is its molecular structure and interaction intensity between solvent and polymer what also depends on that property. Interactions intensity in each system solvent-polymer can be described by the interaction parameter, X. The difference among prepared ethylene-propylene-diene, EPDM, vulcanizate is in the amount of added curative producing different crosslinking densities in thepolymer. An attempt to describe network structure for elastic materials requires, of course, information on the crosslinking density interaction parameter, X, and the crosslinking density, V, were determined by five different methods for five types of EPDM vulcanizates. The used methods were: a) calculation of V from the concentration of the curative, b) "calibrating" the sample with a solvent to form a system for which X is already known, c) stress-strain measurement and determination of the Mooney-Rivlin constant 2C, d) determination of the molecular weight between crosslinking and e) the shear modulus, G, calculation.

EPDM; crosslinking density; Huggins parameter; sweling; stress-strain measurements

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