Polylactic acid composites incorporating casein functionalized cellulose nanowhiskers

Area of Science:

• Materials Science
• Polymer Science
• Biocomposites

Background:

• Polylactic acid (PLA) is a sustainable polymer alternative.
• Cellulose nanowhiskers (CNW) can reinforce PLA, but dispersion is challenging due to hydrophilicity.
• Hazardous surfactants are typically used to improve dispersion.

Purpose of the Study:

• To develop homogenously dispersed CNW-reinforced PLA composites.
• To utilize whole milk casein protein as an environmentally compatible dispersant.
• To investigate the effect of casein on dispersion and mechanical properties.

Main Methods:

• Casein was used as a dispersant for CNWs in PLA.
• Surface plasmon resonance (SPR) imaging assessed casein-PLA affinity.
• Fluorescent staining analyzed CNW dispersion in the PLA matrix.

Main Results:

• Casein significantly improved CNW dispersion in the PLA matrix.
• PLA composites with casein-functionalized CNWs showed higher Young's modulus.
• Improved strain at break was observed at low filler content with casein.

Conclusions:

• Whole milk casein effectively disperses CNWs in PLA, enhancing composite properties.
• Casein's affinity to PLA is crucial for composite strength and stiffness.
• This method offers a sustainable approach to creating high-performance biocomposites.