Tailoring mechanical performance and biodegradability of poly(lactic acid) using renewable additives

Area of Science:

• Materials Science
• Polymer Science
• Sustainable Materials

Background:

• Poly(lactic acid) (PLA) is a widely used bioplastic.
• PLA's applications are limited by its brittleness and slow degradation.
• Enhancing PLA's properties is crucial for broader sustainable use.

Purpose of the Study:

• To improve the toughness and biodegradation rate of PLA.
• To investigate the effects of epoxidized soybean oil (ESO) and epoxidized natural rubbers (ENRs) on PLA properties.
• To explore the impact of different ENR molecular weights (ENR-70k and ENR-250k) on PLA blends.

Main Methods:

• Melt blending of PLA with varying percentages of ESO and ENRs.
• Mechanical property testing (elongation, impact strength).
• Biodegradation assessment via CO2 evolution.
• Analysis of interfacial adhesion using glass transition temperature and fracture surface morphology.

Main Results:

• Incorporation of ESO and ENRs significantly enhanced PLA's elongation (26-30 times) and impact strength (2.0-3.2 times).
• ESO maximized stretchability, while ENR-250k yielded the highest impact strength.
• PLA/ENR-250k blends showed a biodegradation rate of ~74% over 90 days, compared to ~38% for neat PLA.
• Improved interfacial adhesion and chain mobility were observed in the modified blends.

Conclusions:

• Tailored elastomers like ENRs effectively enhance PLA's mechanical properties and accelerate its biodegradation.
• These modifications offer a viable route for developing advanced, environmentally friendly PLA-based materials.
• The study demonstrates a promising strategy for expanding PLA's application in sustainable design.