Chemiluminescence from polypropylene .1. Imaging thermal oxidation of unstabilised film

A chemiluminescence (CL) imaging apparatus based on a cryogenically cooled, slow scan CCD camera was developed to study the thermal oxidation of polypropylene (PP). Experimental procedures and technical limitations are discussed in detail. Images of both thin films and thicker plaques are presented, which show that CL observation is complicated by adverse effects, such as light guiding in film or crack formation in thicker material. This can produce a non-uniform CL signal. CL microscopy images of well crystallised PP are also reported. Results reveal that the method has the sensitivity to examine polymer oxidation at a microscopic level and that the location of oxidation correlates well with the PP morphology.