Pulsed NMR of polymer rubbers and melts

It is well known that the spin-spin relaxation times of protons in condensed polymers are determined by the strength of the homonuclear dipolar coupling between the protons, and are therefore strongly influenced by the presence of chain entanglements involving more than one polymer chain. These chain entanglements may 

More recently Whittaker - re-examined the spin-spin relaxation behaviour of irradiated PE. The decay curves, obtained using the CPMG sequence at 4.30 K, were fitted to the sum of three exponential processes. The most rapid decay 

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