Network properties: 2. A broadline n.m.r. study of molecular motions in some multicomponent crosslinked polymers

A series of multicomponent polymers of known structure and consisting of poly(vinyl trichloroacetate) crosslinked with poly(methyl methacrylate) (PMMA) have been examined by broadline n.m.r. Both enhanced and retarded rotation of the α-methyl groups on the PMMA chains, compared with those in PMMA homopolymer, have been observed. A previous assessment of the morphologies of the same polymers, based on the results of dilatometric studies, has been extended. The modifications to the rotations of the α-methyl groups have been correlated with the morphologies of the multicomponent polymers and it is proposed that both effects arise as a result of changes in the distribution of conformations adopted by the PMMA chains in the multicomponent polymers compared with that in the pure homopolymer.