Polypropylene Dissolution Kinetics: Effects of Solvent, Temperature, and Particle Size

Area of Science:

• Polymer Science
• Chemical Engineering
• Materials Science

Background:

• Polypropylene (PP) is a widely used plastic with low recycling rates.
• Selective dissolution is a promising method for PP recycling from plastic waste.
• Understanding PP dissolution fundamentals is crucial for process development.

Purpose of the Study:

• To develop and validate a model for semicrystalline polypropylene dissolution.
• To gain insights into the kinetics of decrystallization and polymer chain disentanglement.
• To provide time- and position-resolved data on PP dissolution unavailable experimentally.

Main Methods:

• Developed a mathematical model for PP dissolution, considering decrystallization and disentanglement.
• Validated the model using experimental data on PP pellet dissolution kinetics.
• Analyzed the influence of solvent composition and temperature on dissolution.

Main Results:

• Model accurately describes PP decrystallization and dissolution kinetics.
• Key parameters decrease with temperature following an Arrhenius relationship.
• Decrystallization and dissolution times increase with particle size; simultaneous for small particles, sequential for large ones.

Conclusions:

• The model provides critical insights into PP dissolution mechanisms.
• Temperature and particle size significantly impact dissolution rates and times.
• This work supports the optimization of PP dissolution-precipitation recycling processes.