Highly crystallized and tough polylactic acid through addition of surface modified cellulose nanocrystals

Abstract

AbstractTo prepare a fully organic polylactic acid (PLA)‐based bio‐nanocomposite, cellulose nanocrystals (CNCs) were grafted by PLA through ring‐opening polymerization (ROP) of L‐lactide monomers onto CNCs. The grafting process was evaluated by 1HNMR and FTIR spectroscopic methods. The effect of surface‐modified CNCs (M‐CNCs) was investigated on thermal, mechanical, rheological, and dynamic mechanical thermal properties of PLA. The M‐CNCs were successfully dispersed in the PLA matrix. Isothermal and non‐isothermal DSC studies revealed that M‐CNCs caused an intensive increase in crystallization kinetics and therefore nucleation density and crystallization extent. DSC, XRD, and DMTA analyses indicated the formation of different crystal structures [α, α', β] in PLA after addition of M‐CNCs. Rheological analysis was carried out for microstructural investigation of the nanocomposites. Interestingly, after the addition of M‐CNCs not only the tensile strength and modulus of the samples increased but also the toughness of PLA was considerably improved.