Analysis of isotactic polystyrenes obtained with butyllithium and alfin catalysts by carbon‐13 nuclear magnetic resonance spectroscopy

The 13C NMR spectra of polystyrenes, prepared by butyllithium (BuLi) sec‐butyllithium (sec‐BuLi), propyllithium (PrLi), or Alfin catalyst, were measured at 25,03 MHz and the tacticity of the polymers was determined. The formation of mixtures of predominantly isotactic and syndiotactic polymers with BuLi as catalyst in styrene‐water system was ascertained. With sec‐BuLi and PrLi, only atactic polymers were obtained in the same system. The mechanism of the formation of isotactic polymers is discussed. The polymer obtained by Alfin catalyst had stereoblock structure containing rather long isotactic sequences alternating with atactic ones.