Degradation of polyacrylic elastomers: Theoretical and experimental studies

摘要

A series of Reactive Force Field (ReaxFF) molecular dynamics simulation was performed on poly-acrylicester terpolymer for the first time to understand its thermal decomposition characteristics. The effects of time and temperature on the evolution of various products were analyzed. Alkyl radicals were discovered as dominant products at low temperature along with carbon dioxide. Additionally, alkenes were also detected in the final products at higher temperature. Other small molecular products including alkoxy radicals and carbon monoxide were also noticed in the end products. Evolution mechanisms of dominant products (alkyls and alkenes) were explored in detail based on the simulation approach. The fracture of ester linkage is the typical initiation step for the formation of alkyl radicals. The pathway for yielding alkenes mainly consists of the β-hydrogen elimination from the side chain ester groups. The products during the thermal decomposition processes of polyacrylicester predicted theoretically were in agreement with the experimental results from thermogravimetry coupled with fourier transform infrared spectroscopy (TGA-FTIR) and simultaneous thermal analysis coupled with gas chromatography and mass spectroscopy (STA-GC-MS). The apparent activation energy for thermal decomposition of polyacrylicester obtained from the ReaxFF simulation was also consistent with the experimental results.