Preparation and characterization of dry method esterified starch/polylactic acid composite materials

Area of Science:

• Materials Science
• Polymer Chemistry
• Biocomposites

Background:

• Polylactic acid (PLA) is a biodegradable polymer with potential applications in various fields.
• Improving the mechanical properties and processability of PLA is crucial for its wider adoption.
• Corn starch is an abundant and renewable resource that can be modified for material applications.

Purpose of the Study:

• To synthesize maleic anhydride esterified starch using a dry method.
• To investigate the properties of esterified starch/polylactic acid (ES/PLA) composites.
• To evaluate the impact of starch esterification on the compatibility, mechanical strength, water resistance, and melt flow of PLA.

Main Methods:

• Corn starch was esterified with maleic anhydride via a dry method.
• Fourier transform infrared spectroscopy (FTIR) was used for qualitative analysis.
• ES/PLA composites were prepared by melt extrusion.
• Scanning electron microscopy (SEM), tensile testing, bending tests, water resistance tests, melt index determination, and rheological analysis were performed.

Main Results:

• The dry method esterified starch achieved a reaction efficiency of 92.34%.
• ES/PLA composites exhibited enhanced interfacial compatibility, improved tensile strength, bending strength, and elongation at break compared to unmodified starch/PLA.
• Water resistance and melt flow properties of the ES/PLA composites were significantly improved.
• The degree of crystallinity of ES/PLA was lower than that of unmodified starch/PLA (NS/PLA), indicating enhanced interaction.

Conclusions:

• Dry method esterification is an effective way to modify corn starch for enhanced compatibility with PLA.
• ES/PLA composites demonstrate superior mechanical properties, water resistance, and processability.
• This study presents a viable route for developing advanced, sustainable biocomposites from modified starch and PLA.