An Experimental and Numerical Investigation on Bubble Growth in Polymeric Foams

Area of Science:

• Materials Science
• Polymer Science
• Foam Technology

Background:

• Thermoplastic foam morphology critically affects material performance.
• Gas foaming utilizes physical blowing agents like CO2 to create cellular structures.
• Bubble coalescence and film breakage during pressure quench influence final foam architecture.

Purpose of the Study:

• To experimentally investigate carbon dioxide (CO2) bubble growth in a poly(e-caprolactone) (PCL) matrix.
• To employ 3D direct numerical simulations to support experimental observations.
• To rationalize the impact of process parameters on elastic energy and foam morphology.

Main Methods:

• Experimental study of CO2 bubble growth in a PCL matrix under varying pressure conditions.
• Three-dimensional direct numerical simulations of bubble dynamics.
• Extension of analytical models for single bubble growth to multi-mode viscoelastic liquids.

Main Results:

• Demonstrated experimental observation of CO2 bubble growth in PCL.
• Numerical simulations provided insights into elastic energy accumulation during bubble growth.
• Established a correlation between elastic energy, film breakage, and final foam morphology.

Conclusions:

• The study elucidates the relationship between bubble dynamics, elastic energy, and the resulting cellular structure in thermoplastic foams.
• Findings contribute to controlling foam morphology for enhanced material performance.
• The extended viscoelastic model aids in predicting foam structures.