PHOTOOXIDATIVE DEGRADATION OF POLY(ETHYLENE OXIDE)-COPPER CHLORIDE COMPLEXES

Poly(ethylene oxide) (PEG) forms with CuCl2 a complex in acetonitrile (AN) solution as well as in solid phase (after evaporation of solvent) . During u.v. or visible light irradiation it has been observed that a rapid photo-oxidative degradation of the PEO-CuCl2 complex in AN is c aused by free Cl-. and/or Cl-2(.-) radicals (formed from the photolysi s of CuCl2). With increasing degradation processes, there is also a pr onounced change in the morphology of PEO-CuCl2 complexes. They lose th eir capability to form spherulites. This results from changes in molec ular weight and dispersity that affect crystallization conditions. Bot h wide angle X-ray spectroscopy and differential scanning calorimetry show that photodegraded PEO molecules are almost amorphous. Low-molecu lar fractions are formed as a result of chain scission processes. Phot odegradation processes in AN solution do not cause crosslinking or for mation of a gel fraction. Copyright (C) 1996 Elsevier Science Ltd.