Determination of degradation apparent activation energy values of polymers - Regression of kinetic parameters derived from TG data

The isothermal degradation of three aromatic polyetherketones was studied in an inert environment at various temperatures in the range 683-803 K. In the first degradation stage (mass loss Dless than or equal to20%) a linear increase of D as a function of heating time (t) was observed and the corresponding kinetic D=D-o+betat equations at various temperatures were directly drawn by smoothing the experimental TG data. The beta values, which represent the mass loss rates during degradation, increased as a function of temperature according to Arrhenius-type equations, from which degradation E-2 values were determined, which appear in agreement with those from literature methods. Some differences observed were discussed and interpreted.