The role of intra- and intermolecular interactions in determining the conformation and mode of packing of crystalline polymers—I. Poly( cis-1,4-butadiene)

Abstract

Conformational energy calculations on an isolated chain of poly( cis-1,4-butadiene) have been performed, allowing for the variation of all bond angles and torsion angles. Various minimum energy and high symmetry conformations are accessible to the chain. Packing energy calculations have been performed for chains having t ci symmetry, allowing for the variation of symmetry, unit cell constants and internal rotation angles. Unlike the behaviour observed for other polymers, the chain conformation which minimizes the total (conformational plus packing) energy is sensibly different from that of minimum energy for the isolated chain. The agreement between experimental and calculated data of the crystal structure analysis may be considered as very good.