POLYMORPHISM OF THE POLY(ETHYLENE OXIDE)-P-NITROPHENOL COMPLEX

In previous papers, the structure and the spherulitic morphology of the alpha crystal form of the poly(ethylene oxide)-p-nitrophenol molecular complex were described. The observation of another spherulite morphology (beta) of the same compound was now reported. The spherulitic growth rates were found to be significantly lower than those of alpha spherulites, and their melting point was observed 30 degrees C lower. From a polarized FTIR study of these beta spherulites, it appears that they are made of a new allotropic form of the molecular complex which surprisingly corresponds to the same stoichiometry but shows a different polymer conformation and molecular packing. These changes were attributed to the hydrogen bonds involved between host and guest molecules.