Thermal degradation of poly(vinyl chloride) synthesized with a titanocene catalyst

PVC was synthesized using a trichloroindenyltitanium-methylaluminoxane catalyst at room temperature, and its degradation was monitored along with a commercial sample at 160, 170 and 180 °C under air or nitrogen atmosphere. The process was followed by HCl evolution, yellowing index, colour formation and thermogravimetric analysis. The produced polymer had a lower molecular weight and higher surface area, compared with a commercial PVC, while 1H NMR and Tg values show minimal differences between materials. The HCl evolution degradation studies indicate that produced PVC has a lower thermal resistance than commercial PVC, while TGA reveals the opposite behaviour. Yellowing index and colour evaluation give evidence that nitrogen atmosphere and high surface area in produced PVC allow the polyene growth, whereas low surface area and air atmosphere generate shorter polyenes and chromophoric species. Differences in degradation performance are thought to be due to chemical origin, inherent morphology and differences in instrumentation.