Abstract: The correlation functions of the side-groups and side-chains of polymers are obtained for nuclear spin relaxation if the segmental motion of the polymers is described by VJGM model, these functions are derived from unequal two-side and three-site jump internal rotation, diffusion internal rotation, restricted internal rotation and multiple internal rotation. The corresponding spectral density functions are also given, and these functions are used to interpret the nuclear spin relaxation data of the side-groups of some polymers. The average spectral density functions of side-groups are derived under the magic angle spinning, the correlation times and diffusion coefficients of the side-groups of crosslinked poly (methyl methacry-latcs) and solid poly(vinylbutyral) are obtained by using these average spectral density functions. The multiphase structures of nylon 6, poly (ethylenc glycol) and its complexes are investigated with cross-polarization and magic angle spinning techniques.
Three methods using nuclear spin relaxation are presented for studying the intermolecular interaction between polymers and solvents:First, the molecule of tetrachloromethane is used as a "probe" to detect the intermolecular interaction between polymers and tetrachloromethane; Second, the contribution to the spin-lattice relaxation of the quaternary carbons due to the intcrmolecular dipolar interaction is used to calculate the poly (butyl methacrylate)-solvent interaction variables; Third, the intermolecular interaction variables are obtained from the intermolecular heteronuclcar crossrelaxation rates. The heteronuclear cross-relaxation rates are also used to determine the distances among heteromuclei, the general formula for Calculating distances is derived, the experimental results for polymers testify that the formula is correct.
It can be shown with the two-dimensional heteronuclear Overhauser effect technique that the dipolar interaction between the quaternary carbons in polymers and their nearest protons dominates the spin-lattice relaxation of the quaternary carbons. The two-dimensional cadmium-113-proton Overhauser effect spectra of a few cadmium compounds are first reported.