Pyrolytic Kinetics of Polystyrene Particle in Nitrogen Atmosphere: Particle Size Effects and Application of...

Area of Science:

• Polymer Science
• Chemical Engineering
• Materials Science

Background:

• Understanding polystyrene pyrolysis is crucial for polymer degradation studies.
• Particle size is a key factor influencing reaction kinetics and thermal decomposition.
• Existing models may not fully capture the complexities of micro-particle pyrolysis.

Purpose of the Study:

• To investigate the effect of particle size on polystyrene pyrolysis kinetics.
• To identify and modify a suitable pyrolysis model for micro-sized polystyrene particles.
• To analyze the kinetic parameters and reaction steps involved in polystyrene pyrolysis.

Main Methods:

• Utilized isoconversional methods to determine activation energies.
• Applied the Coats-Redfern method to examine pyrolysis models for different particle sizes and heating rates.
• Employed the Avrami-Eroféev model, modified with an accommodation function, as the controlling pyrolysis model.
• Introduced the distributed activation energy method to analyze reaction steps and kinetic triplets.

Main Results:

• The Avrami-Eroféev model, modified as f(α) = n^0.39^(n-1.15)(1-α)[-ln(1-α)]^(1-1/n), effectively explains polystyrene pyrolysis across particle sizes.
• Pyrolysis reaction models are independent of particle geometric dimensions, but reaction rates increase with smaller particle sizes due to increased specific surface area.
• Particle size significantly impacts the first and second step reactions, with smaller particles accelerating the overall pyrolysis process.

Conclusions:

• Particle size is a critical parameter affecting polystyrene pyrolysis rates and kinetics.
• The modified Avrami-Eroféev model provides a robust framework for describing micro-particle pyrolysis.
• Smaller polystyrene particle sizes lead to enhanced pyrolysis efficiency and faster reaction rates.