Additive-Free Multiple Processing of PLA Pre-Consumer Waste: Influence on Mechanical and Thermal Properties

Area of Science:

• Polymer Science
• Materials Science
• Sustainable Materials

Background:

• Poly(lactide) (PLA) is a versatile biopolymer with limited end-of-life options, often ending in landfills.
• Increasing recycling and upcycling rates is crucial for fully utilizing PLA's potential.
• Current biodegradation processes require specific conditions, and landfilling renders PLA similar to conventional plastics.

Purpose of the Study:

• To evaluate the impact of multiple reprocessing cycles on the properties of Poly(lactide) (PLA) pre-consumer industrial waste.
• To determine the feasibility of recycling and upcycling PLA waste without virgin material or additives.
• To assess changes in mechanical, thermal, chemical, and optical properties after 10 reprocessing cycles.

Main Methods:

• Mechanical milling of PLA pre-consumer industrial waste.
• Injection molding of processed PLA.
• Cyclic reprocessing for 10 cycles without virgin PLA or additives.
• Analysis of mechanical, thermal, chemical, and optical properties after each cycle.

Main Results:

• A slight decrease in molecular weight was observed after 10 reprocessing cycles.
• Key thermal properties of Poly(lactide) remained unchanged compared to the initial material.
• Mechanical, chemical, and optical properties were consistently evaluated throughout the reprocessing cycles.

Conclusions:

• Poly(lactide) (PLA) demonstrates resilience through multiple reprocessing cycles, with stable thermal properties.
• The study indicates potential for increased recycling and upcycling of PLA industrial waste.
• Further research could explore methods to mitigate molecular weight decrease during reprocessing.