Conformational study of α- and γ-polypivalolactone based on intra- and intermolecular interactions

Conformational and packing energy of crystalline alpha- and gamma-polypivalolactone has been analyzed with a computational procedure where both intra- and intermolecular interactions are simultaneously taken into account within each energy minimization cycle. This methodological improvement yields results in good agreement with the models directly refined by the powder X-ray diffraction profile and by electron diffraction data. In particular intermolecular interactions prove to have a determinant influence on the detailed conformations of the polymer chain in the two crystalline forms.