Some Aspects of the Thermo-kinetic Non-isothermal Study on the Thermooxidative Degradation of Polytetrafluoroethylene Containing Additives

The thermooxidative degradation of polytetrafluoroethylene (PTFE), both pure and containing additives such as: carbon (graphite) (C), bronze (BZ) and glass fibre (GF), has been studied by non-isothermal thermo-differential analysis (DTA). The values of kinetic parameters obtained from the DTA data, on the basis of thermo-kinetic equations, were compared with the values obtained from the non-isothermal thermogravimetric analysis (TG-DTG) and a good agreement was achieved. The analysis of the characteristic temperatures and of the kinetic parameters from DTA-DTG data revealed that the thermal stability and mechanism of thermooxidative degradation depend on the nature and concentration of additives. The results were confirmed by the existence of a real compensation effect. The following equation was derived for the compensation effect: In A = 0.1410 E - 0.15.