TY - JOUR
T1 - Effect of water content on the thermal degradation of amorphous polyamide 6,6
T2 - A collective variable-driven hyperdynamics study
AU - Arash, Behrouz
AU - Thijsse, Barend J.
AU - Pecenko, Alessandro
AU - Simone, Angelo
PY - 2017
Y1 - 2017
N2 - Thermal degradation under wet conditions is considered as an important aging mechanism in polyamide 6,6 (PA 6,6). The effect of water on thermal degradation of amorphous PA 6,6 is investigated at relatively low temperatures, varying from 1000 to 2000 K, using reactive force field molecular dynamics (MD) and collective variable-driven hyperdynamics simulations. The simulation of the related long-term chemical reactions is made possible thanks to the self-learning accelerated MD concept of hyperdynamics in combination with the corresponding accurate reproduction of the correct dynamics, consistent with unbiased MD simulations. The kinetics of cleavage reactions of the amide bonds in the backbone of the polymer chains, responsible for the thermal degradation of the polymer, is studied, and the influence of water content on the activation energy and pre-exponential factor of the cleavage reactions is explored. The results show that activation energy and pre-exponential factor are in agreement with experimental data. The proposed simulation framework not only estimates kinetic properties of thermal degradation that are consistent with experimental observations but also provides a predictive tool for studying long-term thermal degradation of PA 6,6.
AB - Thermal degradation under wet conditions is considered as an important aging mechanism in polyamide 6,6 (PA 6,6). The effect of water on thermal degradation of amorphous PA 6,6 is investigated at relatively low temperatures, varying from 1000 to 2000 K, using reactive force field molecular dynamics (MD) and collective variable-driven hyperdynamics simulations. The simulation of the related long-term chemical reactions is made possible thanks to the self-learning accelerated MD concept of hyperdynamics in combination with the corresponding accurate reproduction of the correct dynamics, consistent with unbiased MD simulations. The kinetics of cleavage reactions of the amide bonds in the backbone of the polymer chains, responsible for the thermal degradation of the polymer, is studied, and the influence of water content on the activation energy and pre-exponential factor of the cleavage reactions is explored. The results show that activation energy and pre-exponential factor are in agreement with experimental data. The proposed simulation framework not only estimates kinetic properties of thermal degradation that are consistent with experimental observations but also provides a predictive tool for studying long-term thermal degradation of PA 6,6.
KW - Hyperdynamics
KW - Polyamide 6,6
KW - Reactive molecular simulations
KW - Thermal degradation
UR - http://www.scopus.com/inward/record.url?scp=85033222067&partnerID=8YFLogxK
U2 - 10.1016/j.polymdegradstab.2017.10.019
DO - 10.1016/j.polymdegradstab.2017.10.019
M3 - Article
AN - SCOPUS:85033222067
SN - 0141-3910
VL - 146
SP - 260
EP - 266
JO - Polymer Degradation and Stability
JF - Polymer Degradation and Stability
ER -