ABSTRACT
The experimental basis of the investigations of the polyene sequences in degraded PVC is the spectroscopy in the visible and UV range. Such polymers show a number of not very well resolved absorption maxima in their spectra. The wavelength of these maxima is nearly independent of the type of polymer and the kind and mechanism of degradation. The spectra can be analysed assuming that the observed absorption maxima are related to the main absorption bands of the polyene sequences with different lengths. The overall spectrum is therefore formed by the overlapping of the spectra of the different polyenes. It is known that between the number n of double bonds in the sequence and the wavelength A of the absorption maximum at the largest band of a polyene the so-called square root law is valid:
E, = const x n (8.2) On the basis of those assumptions and the Lambert-Beer law it is
possible to calculate the frequency of the polyene sequences of
di11erent length for the conversion x:
(8.3)
where Cp = concentration of the polymer in the testing solution, 10 and J are the light intensities, and d = the ceU path.
