FOIM: Thermal Foaming of Shape Memory Polyurethane Foil

Area of Science:

• Materials Science
• Polymer Chemistry
• Materials Engineering

Background:

• Phase-segregated polyester urethane urea (PEUU) foams offer tunable properties.
• Shape memory materials are sought after for applications requiring volume reduction and recovery.
• Developing efficient synthesis and processing methods for advanced materials is crucial.

Purpose of the Study:

• To introduce and characterize a novel semi-finished product, FOIM, derived from PEUU foam.
• To investigate the shape memory behavior and structural integrity of FOIM after deformation.
• To assess the potential of FOIM for applications demanding low transport volumes and shape change.

Main Methods:

• One-shot synthesis of PEUU foam using poly(1,6-hexylene adipate) diol, 4,4'-methylene diphenyl diisocyanate, polyethylene glycol, and water.
• Characterization using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA).
• Programming the foam via compression at elevated temperature and observing recovery upon reheating.

Main Results:

• Synthesized PEUU foam with a hard/soft segment ratio of 1.06 and 78% open pore content.
• DSC revealed phase transitions at 45°C (melting) and 14°C (crystallization) in the soft segment.
• DMA determined a glass transition temperature of 1°C.
• The FOIM exhibited significant shape recovery from a deformed foil to its original foam structure upon reheating to 60°C.
• Structural integrity was maintained after deformation, as evidenced by buoyancy and heat transmission measurements.

Conclusions:

• FOIM, a PEUU-based material, demonstrates excellent shape memory properties and structural resilience.
• The material's ability to transition between a compressed foil and a foam structure is highly advantageous.
• The ease of manufacture and functionality position FOIM as a promising candidate for applications requiring compact storage and shape adaptability.