Green nanocomposite of (starch/polylactic acid/cellulose nanofiber) thermoplastic

Abstract

Green polymers and nanocomposites are noticed by researchers in the environmental fields. Among them, starch, polylactic acid, and cellulose nanofiber (CNF) are eco-friendly. In the present study, thermoplastic bio-nanocomposites of starch/cellulose nanofiber (SN), polylactic acid/cellulose nanofiber (PN), and starch/polylactic acid/cellulose nanofiber (SPN) are prepared by film casting. The effect of nanofibers is investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), mechanical properties, and water vapor permeability (WVP) of films. Results show that the mechanical properties of SN and PN improve with the addition of CNFs due to their uniform dispersion which are investigated using SEM images. The addition of 1 mL CNF (0.38 wt.%, CNF/solid nanocomposite) satisfactorily enhanced tensile strength and Young’s modulus of SPN (36.99, 629.71 MPa). On the other hand, these properties obtained for SN (6.63, 54.96 MPa) and PN (22.69, 514.61 MPa) with adding 1 mL CNF (1.23 and 0.62 wt.%, CNF/solid nanocomposite). The water vapor permeability of all the films is enhanced slightly with increasing CNF content and it is possible to reduce segmental mobility of polymer molecules at low fiber loading. Due to the excellent mechanical properties and low permeability of SPN nanocomposite, it can be used in the food packaging industry.