E.p.r. relaxation measurements have been made on polymers derived from poly (vinyl alcohol ). Poly (vinyl alcohol) was esterified with three carboxylic acids, one of which was bifunctional, leading to formation of a polymer network. Polymeric samples were studied with two nitroxide sonds and a nitroxide label copolymerized in the main chain. The label had longer correlation times than the sonds. However, the activation energy calculated for the rotational diffusion of the label was lower than that for the radical sonds. In the linear polymers, the size of the side group affected only slightly the rotational motion of the sonds, whereas the rate of motion of the label was very sensitive to variations in the side group.
Посилання на статтю:
E.p.r. studies of spin-probed and spin-labelled poly (vinyl benzoate), poly (vinyl cinnamate) and poly (vinyl diisophthalate) / S. H. O. Egboh*, H. Tenhu and F. Sundholm // Polymer. – 1992. – Vol 33. – P. 1589-1593.