Chain Conformations in the Crystalline Field of Syndiotactic Vinyl Polymers Deriving from 1,3-Diene Monomers. Analysis by Molecular Mechanics

Conformational energy calculations on the chain conformation in the crystalline field have been performed for various syndiotactic vinyl polymers deriving from 1,3-diene monomers. Energy maps as a function of the independent torsion angles have evidenced for all the polymers minima corresponding to highly extended and to helical chains. Energy minimizations as a function of all the internal parameters for the s(2/1)2 and tcm symmetries have allowed the evaluation of the energy differences between chains having the two symmetries and the prediction of the values of the conformational parameters for each polymer. The results have been compared with the experimental data reported in the literature for some of the studied polymers