PERTURBED ENANTIOMORPHIC-SITE MODEL

The perturbed enantiomorphic-site (E) model was developed for the anal ysis of tacticity of Ziegler-Natta polymers. Theoretical probability e xpressions for tacticity diads, triads, tetrads and pentads were deriv ed, and a computer program incorporating perturbed enantiomorphic-site and Bernoullian models was written to facilitate NMR analysis. Exampl es are shown of the use of the perturbed models to study the C-13 NMR tacticity of poly(propylene) made with homogeneous metallocene catalys ts. The perturbed E model is shown to be a suitable theoretical framew ork for the analysis of many polymers made with these catalysts.