Enhanced properties of polylactide by incorporating cellulose nanocrystals

Polylactide (PLA)-cellulose nanocrystal (CNC) bionanocomposites with different CNC loadings were prepared via a simple solvent casting preparation method. Scanning electron microscopy showed some very fine aggregates with a size of 1-3 m whereas transmission electron microscopy revealed the existence of well-dispersed structure of CNCs within the PLA matrix at a nanoscale. The loss and storage moduli of the nanocomposites increased significantly with CNC content, particularly at low frequencies, indicative of a solid-like behavior. The total crystalline content of the PLA in the nanocomposites and the crystallization temperature increased, which were ascribed to the nucleation effect of the CNCs on the crystallization of PLA. The Young modulus of the nanocomposites increased up to 23%, for PLA containing 6 wt% CNC compared to the neat PLA; however, the strain at break slightly decreased. In dynamic mechanical thermal analysis, the storage modulus of the nanocomposites increased up to 74% in glassy region and 490% in the rubbery region. Moreover, using a percolation model, the strength of the percolating CNC network was found to depend on temperature. POLYM. COMPOS., 39:2685-2694, 2018. (c) 2016 Society of Plastics Engineers