Supramolecular Approach for Efficient Processing of Polylactide/Starch Nanocomposites

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Developing sustainable and biodegradable nanocomposites is crucial for reducing environmental impact.
• Poly(l-lactide) (PLLA) and starch nanoplatelets (SNPs) are promising bio-based materials, but processing challenges limit their application.
• Preserving the morphology and properties of nanofillers during composite fabrication is a key challenge.

Purpose of the Study:

• To develop all-biobased and biodegradable nanocomposites of PLLA and SNPs using a novel supramolecular strategy.
• To investigate the role of stereocomplexation and hydrogen bonding in stabilizing SNPs during melt processing.
• To enhance the water vapor uptake and mechanical properties of PLLA/SNPs nanocomposites while preventing degradation.

Main Methods:

• Synthesis of a poly(d-lactide)-block-poly(glycidyl methacrylate) (PDLA-b-PGMA) copolymer via ROP and ATRP.
• Preparation of a PDLA-b-PGMA/SNPs masterbatch using solvent casting with careful solvent selection.
• Melt blending of the masterbatch with PLLA followed by compression molding to produce nanocomposite films.
• Characterization using NMR, SEC, TEM, NIR, TGA, DSC, QCM, and DMTA.

Main Results:

• Successful synthesis of the PDLA-b-PGMA copolymer with controlled architecture.
• Preservation of SNPs morphology during masterbatch preparation and nanocomposite processing due to supramolecular interactions.
• Evidence of stereocomplexation between PLLA and PDLA, and hydrogen bonding between copolymer and SNPs.
• Improved water vapor uptake and mechanical properties, with reduced degradation during melt processing.

Conclusions:

• The developed supramolecular strategy effectively stabilizes SNPs within the PLLA matrix during melt processing.
• Stereocomplexation and hydrogen bonding are key to preserving nanoplatelet integrity and enhancing composite performance.
• This approach offers a promising route for creating high-performance, all-biobased, and biodegradable nanocomposites.