Nuclear magnetic resonance in oriented polymers

The NMR of Polymers

“…130. Relation of the second moment of the line (~H~ of the NMR spectrum of a single crystal oftrioxane to the angle (9') between the C axis of the sample and the field vector at different temperatures [117]: 1) at -26°C; 2) at O·C; 3) at 25'C. Theoretical curves: I) ~H~ for a rigid lattice; II.…”

“…More detailed data on molecular motion in solid trioxane were obtained by us [117] in a study of the NMR' spectrum of single-crystal samples. Figure 130 gives the relation of the second moment of NMR line of trioxane to the angle 6' in the magnetic field at different temperatures.…”

“…·For simplicity the calculations of A Hi in [117] were made for harmonic oscillations of the molecules. Jumps between equilibrium positions are obviously more probable physically than oscillations, t, "C a Fig.…”

“…We determined [118,499] the NMR spectra of poly- oxymethylene obtained by ')I-irradiation of a crystal of trioxane. An x-ray study showed [221] that such a "single-crystal" sample actually consists of crystallites arranged in two ways: with the axis coinciding with the macroscopic axis of the crystal (liZ.…”

“…Relation of the width of the NMR line (6 H) at -196°C to the angle of rotation of a sample of polyaxymethylene in the magnetic field (e')[118]. 1,2) Experimental data for single-crystal and polycrystalline (independent of e') samples; 3) calculated values for the interaction of the protons in CH2 groups of Z crystals of polyox~methylene with a broadening of 8.4 Oe .…”