Novel Nanocomposites Reinforced with Polysaccharide (Starch) Nanocrystals: From Interfacial Ring-Opening Polymerization to Melt-Processing Implementation

A "grafting from" approach was employed to chemically modify the surface of starch nanocrystals (SNCs) with poly(epsilon-caprolactone) (PCL) chains via Sn(Oct)(2)-catalyzed ring-opening polymerization (ROP) of epsilon-caprolactone (CL). The grafting efficiency was evaluated by suspension tests of resulting SNCs grafted with PCL chains (SNC-g-PCL) carried out in toluene as well as infrared analyses. In a subsequent step, the resulting SNC-g-PCL nanohydrids and neat SNCs were melt-blended in a commercial PCL matrix using extrusion techniques in order to investigate the thermo-mechanical properties of resulting bio(nano)composites. The morphological analyses provided by Atomic Force Microscopy showed that the starch nanoplatelets within the SNC-g-PCL nanohydrids maintained their initial morphology and dimensions even after melt-processing at high temperature. Thermo-mechanical properties were evaluated by differential scanning calorimetry and dynamic mechanical thermo-analysis. They showed a substantial improvement of