Some remarks about the conformation of ring polymers in the bulk
and their potential study by small-angle neutron scattering
Polimery 2001, No 11-12, 747
Molten ring polymers are always less viscous than linear polymers identical in nature and molecular weight. The conformation of ring polymers in the bulk is thus believed to be more contracted than that deduced from a Gaussian chain. A model of compaction is suggested, which could be verified by neutron scattering experiments made on an unlabeled block copolymer prepared of identical amounts of ordinary and deuterated monomers, rather than on a deuterium-labeled mixture. Calculation based on this model show the scattering intensity to be affected by compaction quite appreciably and the scattering curve only slightly. A conformation study carried out with a specimen that has been elongated (sheared) could reveal whether compaction is caused by this constraint and to establish the kinetics of compaction.
Keywords: ring vs. linear polymers, compaction, viscosity, neutron scattering by polymers