Bio-Based Poly(lactic acid)/Poly(butylene sebacate) Blends with Improved Toughness

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomaterials

Background:

• Polylactic acid (PLA) is a biodegradable polymer with limited flexibility and toughness.
• Developing sustainable plasticizers is crucial for enhancing PLA's material properties and expanding its applications.
• Bio-derived aliphatic polyesters offer potential as eco-friendly alternatives to conventional plasticizers.

Purpose of the Study:

• To synthesize poly(butylene sebacate) (PBSe) from biomass-derived monomers.
• To investigate the effect of PBSe on the melt processability, flexibility, and toughness of polylactic acid (PLA).
• To evaluate the potential of PBSe as a bio-based plasticizer for PLA.

Main Methods:

• Melt polycondensation of sebacic acid and 1,4-butanediol to synthesize PBSe.
• Melt compounding of PLA with varying concentrations of PBSe (2.5–20 wt%).
• Characterization using torque measurements, melt flow index (MFI), tensile testing, and thermogravimetric analysis (TGA).

Main Results:

• PBSe was synthesized with tunable molecular weights and glass transition temperatures.
• PLA/PBSe blends showed enhanced melt processability and flexibility.
• A PLA/PBSe blend with 20 wt% PBSe exhibited a significant increase in elongation at break (from 2.9% to 108%) with a minor decrease in Young's modulus.
• Thermal properties showed a slight decrease in the presence of PBSe.

Conclusions:

• Synthesized PBSe effectively plasticizes PLA, overcoming its inherent brittleness.
• PBSe demonstrates significant potential as a bio-derived plasticizer for improving PLA's mechanical properties.
• The tunable nature and bio-based origin of PBSe make it industrially relevant for a circular bioeconomy.