Reactive Molecular Dynamics Simulations of Polystyrene Pyrolysis

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Controlled polymer pyrolysis is an economical and eco-friendly method for activated carbon production.
• Understanding the pyrolysis mechanism is crucial for tailoring activated carbon morphology and performance.
• Experimental challenges exist in correlating high-temperature pyrolysis parameters with microstructural evolution.

Purpose of the Study:

• To investigate the pyrolysis mechanism of polystyrene (PS) using reactive molecular dynamics (ReaxFF-MD) simulations.
• To elucidate the influence of heating rates and temperatures on pyrolysis product generation and microstructural development.
• To establish a theoretical framework for optimizing activated carbon synthesis from polymers.

Main Methods:

• Reactive molecular dynamics (ReaxFF-MD) simulations were employed to model polystyrene pyrolysis.
• Simulations were conducted under varying heating rates and temperatures.
• Reduced time plots (RTPs) were used to analyze simulation data and predict activation energy.

Main Results:

• A clear profile of pyrolysis product generation was established, dependent on temperature and heating rate.
• Low heating rates promote a greater diversity of pyrolysis intermediates.
• Optimal temperature ranges were identified for achieving graphitized structures; extreme temperatures are detrimental.
• The predicted activation energy for PS pyrolysis is 159.74 kJ/mol.

Conclusions:

• The study provides a detailed understanding of PS pyrolysis mechanisms under different conditions.
• The findings offer a theoretical basis for controlling activated carbon microstructure during polymer pyrolysis.
• This research facilitates the targeted synthesis of activated carbons with specific morphologies and enhanced performance.