High-resolution solid-state 13C nuclear magnetic resonance study of the combined process of 1H spin diffusion and 1H spin-lattice relaxation in semicrystalline polymers

Abstract

The combined process of spin diffusion and 1H spin-lattice relaxation is measured for uniaxially oriented polyethylene films by high-resolution solid-state 13C nuclear magnetic resonance spectroscopy with the 1H- 13C cross-polarization method. The experimental data are compared with a numerical simulation of the diffusion equation containing the relaxation term in order to estimate 1H spin-diffusion coefficients and 1H spin-lattice relaxation times for crystalline, interfacial and amorphous regions. For these regions, the 1H diffusion coefficients and the relaxation times are estimated as 6 × 10 −12, 6 × 10 −12 and 2.5 × 10 −12 cm 2 s −1 and 4.0, 0.4 and 0.13 s, respectively.