Flexible starch-polyurethane films: Physiochemical characteristics and hydrophobicity

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials

Background:

• Developing sustainable and high-performance composite films is crucial for various applications.
• Starch-based materials often require modification to improve mechanical strength and water resistance.

Purpose of the Study:

• To create novel starch-polyurethane (PU) composite films with enhanced mechanical and hydrophobic properties.
• To investigate the effect of polyethylene glycol-isocyanate (PEG-iso) linker concentration on film characteristics.

Main Methods:

• Microwave-aided gelatinization of high amylose starch (HAGS).
• Grafting of PEG-iso linker onto HAGS to form urethane networks.
• Preparation and characterization of HAGS-PEG-PU composite films, including mechanical testing and contact angle measurements.

Main Results:

• Fourier transform infrared spectroscopy confirmed successful grafting of PEG-iso into the starch structure.
• Increased PEG-iso concentration (up to 20% w/w) improved molecular mixing and interpenetration.
• HAGS-PEG-PU films exhibited significantly improved hydrophobicity (contact angle up to 110°) and flexibility (elongation at break up to 1000%).

Conclusions:

• The developed HAGS-PEG-PU composite films demonstrate superior mechanical and hydrophobic properties.
• The formulation with 20% (w/w) PEG-iso achieved the optimal balance of flexibility and hydrophobicity.
• These findings suggest potential for these advanced starch-based films in diverse applications requiring enhanced performance.