STRUCTURAL STUDIES OF POLYESTERS .8. MOLECULAR AND CRYSTAL-STRUCTURE OF POLYDIKETENE

In the reported experimental investigation, the molecular and crystal structures of polydiketene were studied by IR spectroscopy and x-ray diffraction. It was confirmed from the IR spectra that diketene molecules in the crystal polymerize by ring opening upon gamma -ray irradiation. The unit cell of ther product as polymerized is orthorhombic. The molecule has a conformation shown by the Fischer projection for a lefthanded (2/1) helix; The internal rotation angle around the O - C bond is nearly gauche ( minus 84 degree ), unlike other polyesters. On the basis of x-ray analysis, several molecular conformation models were selected by utilizing calculations of intramolecular interaction energies.