Local motions in poly(ethylene-co-norbornene) studied by (1)H NMR relaxometry.

Molecular motions in poly(ethylene-co-norbornene) were studied in a temperature range well below its glass transition point by a few techniques based on the NMR phenomenon. Temperature dependencies of proton spin-lattice relaxation times T1 (at 200 MHz and at 30.2 MHz), proton spin-lattice relaxation time in the rotating frame T1ρ (at 68 kHz) and frequency dispersion of proton spin-lattice off-resonance relaxation times in the rotating frame T1ρ(off) were determined for the copolymer. Analysis of (1)H NMR relaxation data permitted characterization of local motions occurring in the copolymer i.e. rotation of methyl groups around C3 axes, reorientations of methylene groups and motions of segments of polymer chains including norbornene groups.