Study on Thermal Degradation of High Flow Polyamide 6
The thermal degradation kinetics of high flow polyamide 6(PA6)in nitrogen(N2)and oxygen(O2)atmospheres were studied using thermogravimetric analysis,and the type of thermal degradation mechanism was determined.The results show that the thermal degradation process of PA6 in N2 at different heating rates is a one-step reaction,while it is a two-step reaction in O2.In the high-temperature environment,the polymer exhibits lower initial degradation temperature,maximum weight loss rate temperature,and termination degradation temperature in O2 atmospheres compared to an O2 free environment.In the meanwhile,these characteristic degradation temperatures increase with the increase of the heating rates in N2 and O2 atmospheres.The average thermal degradation activation energies of PA6 in N2 and O2 are determined to be 258.22 kJ/mol and 224.36 kJ/mol respectively,by using three fitting methods:Flynn-Wall-Ozawa(FWO),Kissinger-Akahira-Sunose(KAS),and Tang method.By comparing the activation energies calculated with the Coats-Redfern method for different mechanism functions,it is determined that the thermal degradation mechanism function type of PA6 in N2 and O2 is the third-order deceleration type after random nucleation growth(F3 type).
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