Poly(lactide) Upcycling Approach through Transesterification for Stereolithography 3D Printing

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Manufacturing

Background:

• Mechanical recycling of polylactic acid (PLA) is limited by performance degradation due to thermal and hydrolytic instability.
• Legislative mandates increasingly require recycled and waste content in manufacturing for sustainability.
• Limited reuse options for PLA hinder its contribution to a circular economy.

Purpose of the Study:

• To develop an efficient upcycling route for polylactic acid (PLA) waste into a curable liquid system.
• To investigate the rheological and thermomechanical properties of the resulting PLA-containing systems.
• To demonstrate the feasibility of producing stereolithography (SLA) resins with significant PLA waste content.

Main Methods:

• PLA depolymerization using propylene glycol as a reactant.
• Methacrylation of depolymerized PLA to ensure curability via radical polymerization.
• Rheological and thermomechanical characterization of the synthesized liquid systems.
• Verification of printability for stereolithography (SLA) applications.

Main Results:

• Synthesized curable liquid systems with a wide viscosity range (33–3911 mPa·s at 30 °C).
• Achieved competitive thermomechanical properties: 2240 MPa storage modulus, 164.1 °C glass-transition temperature, and 145.6 °C heat-resistant index.
• Successfully produced SLA resins incorporating up to 51 wt % PLA waste content.
• Demonstrated printability of all developed PLA-containing systems.

Conclusions:

• The developed upcycling process effectively converts PLA waste into valuable curable liquid systems.
• The resulting materials exhibit promising properties for advanced applications like SLA 3D printing.
• This method offers a sustainable solution for PLA waste management and promotes the circular economy in polymer manufacturing.