Degradation of Poly(vinyl Chloride) with Different Additives, Studied by Micro Raman Spectroscopy

Raman spectroscopy was employed for studies of the thermal degradation of poly(vinyl chloride). Intensity enhancement of vibrations belonging to conjugated double bond sequences in the corresponding spectra allowed the detection of degradation at the very first stage. In this initial period, the kinetics of degradation showed a linear increase in conjugated sequences. Furthermore, the influence of additives on the resistance to thermal stress was investigated by the same method. Plots showing the development of conjugated sequences in the presence of calcium stearate, zinc stearate, and zinc chloride are presented. They are compared with the results for unstabilised poly(vinyl chloride). A clearly positive development in thermal behaviour could be observed upon stabilisation, and predicted reaction mechanisms for single components were confirmed. The goals of this work were: (i) to use Raman spectroscopy for fundamental investigations into the working principles of stabilisers; and (ii) to contribute towards more effective formulations for poly(vinyl chloride) stabilisation, with low ecological impact.