Reactive molecular dynamics simulation for analysis of thermal decomposition of oligomeric polyacrylicester model nanocomposite and its experimental verification

Molecular dynamics simulation was performed for the first time on oligomeric poly(ethylene-co-ethylacrylate-co-n-butylacrylate) (ACM) chains, consisting of ten repeating monomer units in presence and absence of model silica particle to investigate the influence of nanosilica on high- temperature degradation characteristics of ACM nanocomposite. The initial decomposition temperature and the final degradation temperature were increased while the rate of degradation of ACM decreased with the introduction of silica molecules. Alkyl radicals, alkenes and carbon dioxide as the dominant products were detected during the reactive simulation. Other small molecular products including carbon monoxide and alkoxy radicals were discovered in the eventual products as well. Furthermore, pyrolysis gas chromatography-mass spectrometry (py-GC-MS) was used to identify the decomposition products obtained from the degradation of ACM at high temperature and the results were compared with the prediction from atomistic modelling. The activation energy of degradation for ACM was also calculated from the reactive simulation as well as from the thermogravimetric analysis and gel permeation chromatography (GPC). The results of the ReaxFF molecular dynamics simulations were consistent with all the experimental observations. The current study would help in understanding and improve the thermal stability of various polymers in industrial applications. (c) 2018 Elsevier Ltd. All rights reserved.