The influence of the tacticity on thermal degradation of PVC. II. New results obtained with fractionated polymers

PVC samples prepared in bulk at 40, 0, and −50°C were fractionated by different methods. The samples were characterized by viscosimetric measurements and by IR spectroscopy in order to determine the tacticity. The thermal degradation of the samples was studied at 175, 180, and 185°C by means of continuous measuring of the evolved HCl in a conductivity apparatus. From the kinetic results and the UV‐visible spectra recorded on equally degraded samples follows that syndiotactic sequences give rise to high degradation rates as well as to long polyene sequences in agreement with results previously obtained with unfractionated polymers.