A 13C-NMR investigation of plasma polymerized ethane,ethylene, and acetylene

Solid-state ¹³C-NMR spectra were obtained by cross-polarization and magic angle spinning of polymers prepared by injecting ethane, ethylene, and acetylene into a radiofrequency plasma. By use of the delayed decoupling technique to suppress protonated carbon peaks and difference spectroscopy five resolved spectral bands can be distinguished. These bands are assigned to (I) unsaturated nonprotonated, (II) unsaturated CH and CH₂, (III) quaternary, (IV) methine and methylene, and (V) methyl carbons by comparison with standard ¹³C shifts compiled for organic materials. The relative amounts of these structural features in the polymers were determined quantitatively and the possible sources of errors considered.