Mobility of polyethylene chains in the orthorhombic and hexagonal phases investigated by NMR

This is a report on a study of polyethylene, in and near the hexagonal phase, using NMR. From proton and deuteron NMR lineshapes and spin–lattice relaxation rates, we determine the rate and type of motion of the polyethylene chains both in the orthorhombic and hexagonal phase. In the hexagonal phase, we find fast axial local motion in combination with fast chain diffusion, which is in marked contrast to the more restricted motion we observe in the orthorhombic phase.