Solid-state 13C NMR studies of the morphology and orientational order of polymer fibers

The author conducted detailed studies of the morphology of as-spun PET (poly(ethylene terephthalate)) and gel-spun PE (poly(ethylene)) fibers by 13C CP/MAS (Cross Polarization/Magic Angle Spinning) NMR technique. The presence of multiple-component resonance line-shapes allows one to calculate the true population of various morphological components, after correcting for pin relaxation effects. From these NMR measurements, two different models for PET and PE polymer systems are proposed. The advanced two-dimensional rotor synchronized MAS (2D ROSMAS) technique was also used to study the orientational order of various morphological components. A wide range of orientational order is clearly displayed on 2D spectra for samples under different fabrication conditions. A regression simulation program was used to deduce the order parameter used in computing the orientational distribution function (ODF) for each component