The comparative kinetic analysis of non-isothermal degradation process of acrylonitrile–butadiene/ethylene–propylene–diene rubber blends reinforced with carbon black/silica fillers. Part II

The non-isothermal degradation processes of acrylonitrile–butadiene/ethylene–propylene–diene rubber blends reinforced with carbon black/silica fillers were investigated with thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG), using the different calculation procedures. Using differential and integral isoconversional methods, it was found that the NBR/EPDM 70 phr SiO2, NBR/EPDM 35 phr carbon black/35 phr SiO2 and NBR/EPDM 50 phr carbon black/20 phr SiO2 degradations represent complex processes, with existing conversion regions of constant apparent activation energy (Ea). It was found that the degradation process of the NBR/EPDM 70 phr SiO2 under nitrogen atmosphere can be described by the one and a half order (n = 3/2; F3/2) kinetics, while the degradation of the NBR/EPDM 35 phr carbon black/35 phr SiO2 and NBR/EPDM 50 phr carbon black/20 phr SiO2 can be described with two- (D2) and three- (D3) dimensional diffusion mechanisms. For all investigated systems, an artificial compensation effect (art-CE) was found. Good agreement was observed between the experimental and calculated conversion curves, for all considered degradation processes. It was found that the sample of the polymer blend, which contains the highest carbon black content (50 phr carbon black), shows the greatest self-protective behavior.