High-Toughness Poly(Lactic Acid)/Starch Blends Prepared through Reactive Blending Plasticization and...

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials

Background:

• Poly(lactic acid) (PLA) is a biodegradable polymer with limitations in toughness.
• Starch is an abundant, low-cost biopolymer, but its compatibility with PLA is poor.
• Improving the mechanical properties and interfacial adhesion of PLA/starch blends is crucial for wider applications.

Purpose of the Study:

• To enhance the toughness and compatibility of poly(lactic acid)/starch blends.
• To investigate the role of citric acid (CA) and polyethylene glycol (PEG) in modifying PLA/starch blends.
• To explore the potential of these modified blends in medical and packaging applications.

Main Methods:

• Reactive melt blending of PLA and starch with CA and PEG.
• Mechanical performance testing (elongation at break, impact strength).
• Material characterization using SEM, DSC, FTIR, XRD, rheology, and hydrophilicity tests.

Main Results:

• The PLA/starch/PEG/CA blend exhibited significantly improved elongation at break (140.51%) and impact strength (3.56 kJ·m⁻²).
• Esterification reactions between CA, PEG, and starch enhanced interfacial adhesion and compatibility.
• PEG acted as a plasticizer, increasing molecular chain mobility and forming a compatibilizing copolymer.

Conclusions:

• Reactive melt blending with CA and PEG effectively improves the toughness and compatibility of PLA/starch blends.
• The esterification reaction is key to enhancing interfacial adhesion and material properties.
• Modified PLA/starch blends show promise for applications in medicine and high-fill packaging, with minimal impact on PLA biodegradability.