Solid state NMR studies of novel polycarbosilanes, allylhydridopolycarbosilane derived silicon carbide, and inorganic PMMA nanocomposites

Many studies involving polymeric systems incorporate solid-state nuclear magnetic resonance as part of the research process, for example, the physical and chemical properties of fluoro and cyano substituted poly(silylenemethylenes) have been studied. Use of magic angle spinning (MAS) and variable temperature (VT) NMR spectroscopy provide insights into crystallinity and structure.; 2H wideline NMR spectroscopy is employed in the study of motion and crystallinity of polysilaethylene (PSE) (the organosilicon analog of polyethylene). In addition, analytical spincounting and T₁ relaxation provide additional insights into the segmental motion and the nature of the crystalline state of PSE. VT 2H wideline NMR studies near the glass transition elucidate the nature of chain motions allowed.; Silicon carbide derived from the pyrolysis of allylhydridopolycarbosilane has been studied with 29Si MAS. The short range order is revealed by these spectra. The crystalline order and stacking faults are evidenced by the chemical shifts and the multicomponent relaxation behavior.; PMMA TiO₂ nanocomposites have been investigated with a variety of techniques, including VT 1H wideline studies, to reveal segmental motion of the composite materials relative to unfilled PMMA. Silane coupling agents can compatiblize the surface of the nanosized oxide. Si NMR has been able to show the nature of the bonding. In addition, an analytical technique of combined rotation and multiple pulse spectroscopy (CRAMPS) spincounting can quantify the amount of silane coupling agent that reacts with the surface of the oxide particles.