Effects of maleated ethylene propylene diene rubber (EPDM) on the thermal stability of pure polyamides, and polyamide/EPDM and polyamide/poly(ethylene terephthalate) blends: kinetic parameters and reaction mechanism

The effects of maleated ethylene propylene diene (EPDM-g-MA) on the thermal stability of polyamide/EPDM and polyamide/ poly(ethylene terephthalate) (PET) systems were studied by thermogravimetric analysis and infrared spectroscopy in nitrogen. Based on the activation energy (E) and reaction products, it is suggested that the thermal degradation of pure polyamide 12.10 (PA-12.10) and polyamide 6.10 (PA-6.10) occurred firstly by chain scission of the weakest C-N and -C(O)-NH bonds. The average value of E for pure PA-12.10 was ca. 280 kJ mol(-1). In the binary and ternary blends, the decrease of E to ca. 180-200 kJ mol(-1) indicated a more favourable degradation. For the systems containing PA-6.10, E decreased from ca. 210 kJ mol(-1) (pure PA-6.10) to ca. 160 kJ mol(-1) in the ternary blends. The results suggest that the presence of EPDM-g-MA in the blend decreased the thermal stability of the polyamides. (C) 2001 Elsevier Science Ltd. All rights reserved.