Molecular and Crystal Structures of Poly (ethylene oxybenzoate) : α Form

Abstract

The crystal structure of poly (ethylene oxybenzoate) α form was determined by x-ray analysis and intra- and intermolecular interaction potential energy calculations, i.e., the crystal structure model was refined by using a packing energy minimization method prior to the least-squares refinement in x-ray analysis. The unit cell is orthorhombic, P212121, with α = 10.49 Å, b = 4.75 Å, and c (fiber axis) = 15.60 Å. The two antiparallel (2/1) helical chains are located at the center and the corner of the unit cell. The internal rotation angles are [formula omitted] where the angle (-13°) is for the virtual bond (O-Ph-C) and the dihedral angle (-15°) is defined by the planes of the benzene ring and the ester group. The chain has a zigzag conformation of large scale, one monomeric unit being a large zigzag unit. The low crystallite modulus of the α form is explained by this molecular structure. © 1977, American Chemical Society. All rights reserved. © 1977, American Chemical Society. All rights reserved.