engleski

The Influence of Network on the Interaction Parameter x in System EPDM Vulcanizate-Solvent

Flory-Huggins interaction parameter x was determined for the samples of EPDM vulcanizates, Keltan 312,812 and their mixtures 312/812. Crosslink density was varied by changing the amount of dicumyl peroxide added during miling, then samples were vulcanized. The uniaxial sterss-strain measurements were made on networks to determined the crosslink density. Prepared samples were swelled in following solvents; cyclohexane,n-xylene, n-heptane, toluene,tetrahydrofuran and benzene, which interaction parameters x are well known. The values of interaction parameter xc were obtained for EPDM vulcanizate and quoted solvents by equilibrium swelling from Flory-Rehner equation. The values of x, known from literature, were compered with obtained interaction parameter xc. Structural factor F"4, additionally characterize the investigated networks, was determined by equilibrium swelling. The difference between the interaction parameters xc calculated from Flory-Erman equation, where is structural factor take in count, and Flory-Rehner equation indicate that network has an influence on interactions in system polymer-solvent. From the results it can be also concluded that the values of x parameter are distinct for crosslinked and uncroslinked polymer.

Crosslink density;EPDM-vulcanizate;Flory-Huggins interaction parameter;network;solvent

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