Local Anisotropy of the Side Group Motion in the Melts and Swollen Gels of Cross-Linked Comb-Like Polymers
Titel:
Local Anisotropy of the Side Group Motion in the Melts and Swollen Gels of Cross-Linked Comb-Like Polymers
Auteur:
Gasilova, E. R. Shevelev, V. A. Budovskaya, L. D. Ivanova, V. N.
Verschenen in:
International journal of polymeric materials
Paginering:
Jaargang 19 (1993) nr. 1-2 pagina's 41-49
Jaar:
1993-01-01
Inhoud:
We have investigated the 1H and 19F spin-spin relaxation behavior in the melts and swollen gels of cross-linked polyfluoroalkyl acrylates PFA-nR where n is the number of CF2 groups in the side chain (n = 2, 3, 4). It was found that in the strands the anisotropic motion of the main chain units and the side groups lead to the non-zero degree of averaging of magnetic dipole-dipole interactions (Q). Q of side groups was estimated to depend on the degree of cross-linking Q ≈ blx, where x is the number of persistent lengths in the strand, b was found to decrease with increasing n. In opposite to PFA-3F and PFA-2H networks, the dangling ends in PFA-4R network were shown to influence the relaxation behavior, indicating the growth of motional anisotropy of dangling ends with chain diameter.