Abstract
The effects of polylactide-graft-cellulose nanocrystals on the thermal and mechanical properties of poly(l-lactide) matrices were investigated. Cellulose nanocrystals (CNCs) were grafted with polylactide chains via a solvent-free process by ring-opening polymerization of l-lactide using magnesium hydride as a catalyst. The efficiency of grafting was determined by infra-red, X-ray photoelectron spectroscopy and nuclear magnetic resonance analyses. X-ray diffraction analyses showed that the crystalline nature of the CNCs was preserved. Nanocomposites based on poly(l-lactide) matrix containing ungrafted nanocrystals (PLLA/CNCs) and grafted nanocrystals (PLLA/PLLA-g-CNCs) were investigated. DSC revealed that the grafted nanocrystals exhibited a strong influence on the crystallinity of the nanocomposites, inducing a significant enhancement of the mechanical properties of PLLA/PLLA-g-CNCs compared with PLLA/CNCs material. The role played by the polylactide grafted layer on the interaction between the CNCs and PLLA matrix was revealed by mechanical analyses in the solid and molten states.