Modelling Gas Transport in Multiphasic Materials: Application to Semicrystalline Membranes.

Area of Science:

• Materials Science
• Polymer Science
• Chemical Engineering

Background:

• Gas permeation in heterogeneous materials is well-studied for composites.
• Existing models often focus on low filler content and high aspect ratios.
• Semicrystalline polymers present unique challenges due to varying crystalline fractions.

Purpose of the Study:

• Extend gas permeation models to semicrystalline polymers.
• Investigate the impact of crystalline morphology on gas transport.
• Develop predictive models for tortuosity in these materials.

Main Methods:

• Numerical simulation using random sequential adsorption and Voronoi tessellation for microstructure generation.
• Finite volume method to solve local mass balance and calculate flux reduction.
• Analysis of crystallite arrangement, size, orientation, and shape effects.

Main Results:

• Quantified flux reduction due to impermeable crystalline domains.
• Identified key morphological parameters influencing relative permeability and tortuosity.
• Established relationships between microstructure and macroscopic transport properties.

Conclusions:

• The study provides a framework for understanding gas permeation in semicrystalline polymers across diverse crystalline volume fractions.
• Proposed new analytical equations improve tortuosity prediction for membranes and barrier materials.
• Morphological effects are crucial for accurate modeling of gas transport in semicrystalline polymers.