Reprocessing of PLA/Graphene Nanoplatelets Nanocomposites

Area of Science:

• Polymer Science and Engineering
• Materials Science
• Nanocomposites

Background:

• Poly(lactic acid) (PLA) is a biodegradable polymer with potential applications in various fields.
• Repeated melt processing can degrade polymers, affecting their properties and performance.
• Graphene nanoplatelets (GnP) are known to enhance polymer properties, but their effect on reprocessing stability needs investigation.

Purpose of the Study:

• To investigate the impact of multiple melt reprocessing cycles on the properties of poly(lactic acid) (PLA) filled with graphene nanoplatelets (GnP).
• To compare the degradation behavior of GnP-filled PLA with neat PLA during reprocessing.
• To evaluate the effect of reprocessing on GnP dispersion within the PLA matrix.

Main Methods:

• Materials: Poly(lactic acid) (PLA) and PLA filled with graphene nanoplatelets (GnP).
• Processing: Materials were melt reprocessed up to five times using a single-screw extruder.
• Characterization: Morphological, X-Ray Diffraction (XRD), Micro-Raman spectroscopy, intrinsic viscosity, thermal, rheological, and mechanical tests were performed.

Main Results:

• Graphene nanoplatelets (GnP) significantly reduced the degradation rate of poly(lactic acid) (PLA) with increasing reprocessing cycles compared to neat PLA.
• Neat PLA exhibited a more pronounced reduction in molecular weight after multiple reprocessing cycles.
• Reprocessing improved the dispersion of GnP within the PLA matrix and decreased the formation of GnP aggregates.

Conclusions:

• Incorporating graphene nanoplatelets (GnP) enhances the stability of poly(lactic acid) (PLA) against degradation during multiple melt reprocessing cycles.
• GnP-filled PLA demonstrates superior performance retention after reprocessing compared to neat PLA.
• The study highlights the potential of GnP as a reinforcing agent to improve the processability and durability of PLA.