Deuterium magnetic resonance on elongated networks: orientational order versus network structure
The orientational order generated in uniaxially strained (end-linked) polydimethylsiloxane rubbers is investigated as a function of the length of the precursor chains and of the polymer concentration at which the network was formed. The degree of orientational order was measured by means of the deuterium NMR technique performed on labelled network chains. The induced order increases with the density of crosslinking junctions and trapped entanglements. The observed effects are analysed versus the equilibrium swelling degree of the samples, in order to characterize the real network structure with respect to chain segment ordering.
Key wordsrubber polydimethylsiloxane deuterium NMR orientational order trapped entanglements
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