Synthesis of Lignin and PLA/PBAT Films: Biodegradability and Environmental Impacts

Area of Science:

• Materials Science
• Polymer Science
• Environmental Science

Background:

• Biodegradable polymers like poly (lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are crucial for sustainable packaging.
• Improving the interfacial adhesion and biodegradability of PLA/PBAT blends is essential for enhanced performance.

Purpose of the Study:

• To synthesize and characterize biodegradable PLA/PBAT films with lignin as a natural additive.
• To optimize the formulation using dicumyl peroxide (DCP) as a compatibilizer and evaluate the impact of lignin concentration.
• To assess the mechanical, thermal, and biodegradation properties, alongside the environmental footprint.

Main Methods:

• Film synthesis using poly (lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends.
• Incorporation of lignin (0.005-0.02%) and dicumyl peroxide (DCP) as a compatibilizer.
• Characterization via SEM, FTIR, XRD, TGA, mechanical testing, soil burial tests, and life cycle assessment (SimaPro, ReCiPe).

Main Results:

• Optimized PLA/PBAT ratio (70:30) with DCP improved interfacial adhesion.
• Lignin addition enhanced tensile strength, elongation at break, and thermal stability.
• The optimal formulation achieved a 44.22% degradation rate after 90 days of soil burial.
• The film with 0.005% lignin exhibited the lowest environmental impact in the life cycle assessment.

Conclusions:

• Small amounts of lignin significantly improve the biodegradability and mechanical properties of PLA/PBAT films.
• Lignin acts as an effective additive to enhance the performance of these biodegradable films.
• The developed lignin-modified PLA/PBAT films show promise for eco-friendly packaging solutions.
• Life cycle assessment identified solvent use as a key contributor to ecotoxicity, guiding future material development.