Conformational and packing stability of crystalline polymers. III. Simplified method of energy calculations to set up helical molecular models for X-ray analysis

Abstract

A simplified method of intramolecular energy calculations was derived to set up helical molecular models for X-ray analysis. The calculation is made only for the possible conformations permitted by the fiber identity period, and the numbers of monomeric units and of turns in the fiber period. By utilizing the initial X-ray data, the number of variables for energy calculations is reduced. This method was applied to poly(ethylene oxide) and isotactic poly(propylene oxide) in order to confirm the validity, and the calculated stable conformations gave good coincidence with the results of X-ray analyses.