Reactive molecular dynamics simulation for analysis of thermal decomposition of oligomeric polyacrylicester model nanocomposite and its experimental verification. (14th February 2018)

• Record Type: Journal Article
• Authors: Saha, Tuhin; Bhowmick, Anil K.; Oda, Takeshi; Miyauchi, Toshiaki; Fujii, Nobuhiko
• Is Part Of: Polymer. Volume 137(2018)
• Page Start: 38
• Page End: 53
• Publication Date: 2018-02-14
• Subjects: Acrylic rubber -- Degradation -- Thermal stability -- Molecular dynamics simulation; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2017.12.043
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: 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. Graphical abstract: Image 1 Highlights: Pyrolysis of polyacrylicester model compound investigated in presence of model silica using molecular dynamics simulation. Alkyl radicals, alkenes and carbon dioxide were identified as major pyrolysis products. The elevated final temperature decreases the initial degradation temperature and shortens the initiation time. The presence of nanosilica enhanced the thermal and oxidative degradation of polyacrylicester model compound. The mechanism and activation energy of degradation agree with the results from Py-GCMS and TGA.