Open-Celled Foams from Polyethersulfone/Poly(Ethylene Glycol) Blends Using Foam Extrusion

Area of Science:

• Materials Science
• Polymer Chemistry
• Chemical Engineering

Background:

• Batch foaming of polyethersulfone (PESU) is limited to small scales and slow production rates.
• High processing temperatures (≥320°C) for PESU hinder energy efficiency and sustainability in foam production.

Purpose of the Study:

• To develop a large-scale, continuous production method for highly porous PESU foams.
• To reduce the processing temperature of PESU foam extrusion using blends with poly(ethylene glycol) (PEG).

Main Methods:

• Utilized foam extrusion with carbon dioxide (CO2) and water as physical foaming agents.
• Prepared partially miscible PESU/PEG blends via material penetration, avoiding organic solvents.
• Characterized thermal, rheological, and CO2 sorption properties of homopolymers and blends.

Main Results:

• Achieved a significant reduction in processing temperature by approximately 100°C.
• Optimized blend composition and processing parameters (lower nozzle temperature, CO2/water foaming agents) for high porosity.
• Produced foams with ~51% porosity and an average cell diameter of 5 µm, the lowest reported for extruded polymer foams.

Conclusions:

• PESU/PEG blends enable energy-efficient and sustainable large-scale production of highly porous foams.
• The developed extrusion foaming process offers a significant advancement over traditional batch methods.
• The study demonstrates a viable route to ultra-fine cell extruded polymer foams.