Precise Modeling of the Particle Size Distribution in Emulsion Polymerization: Numerical and Experimental Studies for...

Area of Science:

• Polymer Chemistry
• Chemical Engineering
• Computational Modeling

Background:

• Particle size distribution (PSD) modeling in emulsion polymerization (EP) faces challenges with existing pseudo bulk (PB) and 0-1/0-1-2 models.
• Experimental PSDs often appear broader than theoretical predictions, indicating limitations in current modeling approaches.
• Solving the hyperbolic partial differential equations (PDEs) for PSD evolution requires precise and robust numerical techniques.

Purpose of the Study:

• To develop and investigate a deterministic kinetic model for ab initio EP PSD evolution.
• To compare the Finite Volume (FV) and weighted-residual methods for solving the model's PDEs.
• To address the controversy regarding the appropriate model type for simulating experimental PSDs in EP.

Main Methods:

• Developed a deterministic kinetic model incorporating micellar nucleation and particles with n≥0 radicals.
• Employed and compared Finite Volume (FV) and weighted-residual numerical methods to solve the system of PDEs.
• Validated the model using experimental data for styrene and methyl methacrylate homopolymerization and copolymerization.

Main Results:

• The pseudo bulk (PB) model exhibits a structural limitation in adequately representing PSDs with steep fronts.
• The Finite Volume (FV) method's limitations were identified.
• No generalized evidence supports the addition of stochastic terms to enhance deterministic EP models' PSD prediction.

Conclusions:

• The pseudo bulk (PB) model is discouraged for simulating broad PSDs in emulsion polymerization.
• Deterministic kinetic models are sufficient for PSD prediction in EP, without a generalized need for stochastic terms.
• Accurate numerical methods are crucial for reliable PSD evolution modeling in EP.