Structural characterization and properties of polyols plasticized chitosan films

Area of Science:

• Materials Science
• Polymer Chemistry
• Food Science

Background:

• Chitosan films are promising for food packaging due to their biodegradability and film-forming properties.
• Incorporating plasticizers is crucial for modifying chitosan's mechanical and thermal characteristics.
• Understanding polyol interactions is key to optimizing chitosan film performance.

Purpose of the Study:

• To investigate the effects of glycerol, xylitol, and maltitol on chitosan film crystallinity and thermal behavior.
• To elucidate the role of polyols versus moisture in plasticizing chitosan.
• To assess how polyol addition impacts mechanical properties like tensile strength and ductility.

Main Methods:

• X-ray Diffraction (XRD) for crystalline structure analysis.
• Fourier Transform Infrared Spectroscopy (FTIR) to study molecular interactions.
• Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) for thermal properties.

Main Results:

• Polyols weakened hydrogen bonding in chitosan, while moisture promoted crystallization.
• Glycerol-plasticized films exhibited lower glass transition (Tg) and melting temperatures (Tm), indicating higher moisture content.
• Tensile strength decreased, but ductility improved with polyol incorporation.

Conclusions:

• Polyols effectively plasticize chitosan films, regulating microstructure and properties.
• Moisture plays a more significant role in chitosan crystallization than the polyols themselves.
• These findings are vital for tailoring chitosan films for specific food industry applications.