Lifetime simulation and thermal characterization of PVC cable insulation materials

Thermal behavior of commercial PVC cable insulation both before and after extraction of plasticizers, fillers and other agents were tested by TG/DTG and DSC during heating in the range 20-800°C in air. The ultrasound enhanced hexane extraction and dissolution in THF with subsequent precipitation of PVC were used to prepare 'extracted' and 'precipitated' samples. The total mass loss measured for the 'non-treated', 'extracted' and 'precipitated' PVC samples was 71.6, 66.6 and 97%, respectively. In the temperature range 200-340°C the release of dioctylphthalate, HCl and CO₂was observed by simultaneous TG/FTIR. From TG results measured at different heating rates (1.5, 5, 10, 15 K min^-1) in the range 200-340°C the non-isothermal kinetics of the PVC samples degradation was determined. Activation energy values of the thermal degradation processes calculated by ASTM E 698 method, for 'non-treated', 'extracted' and 'precipitated' PVC samples were 174.6±17 kJ min^-1, 192.8±19 kJ min^-1, 217.1±20 kJ min^-1, respectively. These kinetic parameters were used for the lifetime simulation of the materials.