Pentad tacticity of polymethacrylonitrile through 13C‐NMR spectroscopy

The pentad stereochemical placements in polymethactylonitrile were analyzed by using proton‐decoupled natural abundance FOURIER transformed 13C‐NMR spectra. The data of pentad microtacticity were used to examine the stereospecific polymerization mechanisms. Two types of polymethacrylonitrile were used. The relative intensities of pentad peaks for the polymer prepared with free radical catalyst by bulk polymerization at 80°C were reasonably interpreted by the BERNOULLIan model. Those for the polymer, prepared with diethylmagnesium in toluene at 70°C, may be described by both the stereoblend model and the firstorder MARKOVian model, but not by BERNOULLIan model.