All-biobased and biodegradable nanocomposites consisting of poly(l-lactide) (PLLA) and starch nanoplatelets (SNPs) were prepared via a new strategy involving supramolecular chemistry, i.e., stereocomplexation and hydrogen-bonding interactions. For this purpose, a poly(d-lactide)-b-poly(glycidyl methacrylate) block copolymer (PDLA-b-PGMA) was first synthesized via the combination of ring-opening polymerization and atom-transfer radical polymerization. NMR spectroscopy and size-exclusion chromatography analysis confirmed a complete control over the copolymer synthesis. The SNPs were then mixed up with the copolymer for producing a PDLA-b-PGMA/SNPs masterbatch. The masterbatch was processed by solvent casting for which a particular attention was given to the solvent selection to preserve SNPs morphology as evidenced by transmission electron microscopy. Near-infrared spectroscopy was used to highlight the copolymer–SNPs supramolecular interactions mostly via hydrogen bonding. The prepared masterbatch was melt-blended with virgin PLLA and then thin films of PLLA/PDLA-b-PGMA/SNPs nanocomposites (ca. 600 μm) were melt-processed by compression molding. Theresulting nanocomposite films were deeply characterized by thermogravimetricanalysis and differential scanning calorimetry. Our findings suggestthat supramolecular interactions based on stereocomplexation betweenthe PLLA matrix and the PDLA block of the copolymer had a synergeticeffect allowing the preservation of SNPs nanoplatelets and their morphologyduring melt processing. Quartz crystal microbalance and dynamic mechanicalthermal analysis suggested a promising potential of the stereocomplexsupramolecular approach in tuning PLLA/SNPs water vapor uptake andmechanical properties together with avoiding PLLA/SNPs degradationduring melt processing.
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