Isothermal aging tests by thermogravimetry

The present results of thermogravimetry indicate that 165 °C is still too low a temperature to initiate an oxidation process. Therefore isothermal aging tests were carried out for 120 minutes at 250 °C both in argon and in air. Samples of approximately 5 mg weight were 

0 loss in argon higher than in air Q = 1.0 equal losses in air and in argon 2 1.0 loss in air higher than in argon 

Quotient Q (Loss in Air/Loss in Argon) versus Time 

The influence of the concentration of the dispersion medium or the maltenes and their average relative particle mass M is seen. If we define this influence using factors  

Pj = (concentration of dispersion medium) M = (concentration of petroleum resins) M, 

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