Poly (Methyl methacrylate) /Poly (lactic acid) /Cellulose Nanocrystals Packaging Film. Part I: CNC Surface Modification, Nanocomposite Preparation and Characterization

Bio-plastic films from renewable resources are appropriate replacement for conventional plastic films. In this study, nanocomposite films were prepared by using polylactic acid (PLA), poly(methyl methacrylate) (PMMA), and cellulose nanocrystals (CNC). The surface of CNC was modified by using a surfactant (at different ratios), in order to make CNC more compatible with PLA. The surfactant modified the surface of CNC without changing length and diameter of CNC. The polarity of CNC surface depended on the ratio of surfactant to CNC that was used for the modification. Adding CNC to PMMA/PLA blends reduced the transparency of the films, although nanocomposite films were still transparent. An increase in PMMA and CNC contents of the film led to increase the contact angle. An increase in PMMA content of the film reduced glass transition temperature (Tg) and melting point (Tm). Inversely, addition of CNC to PLA/PMMA blends increased Tg and Tm, though there were some fluctuations, caused by dispersion quality of CNC in the matrix. The results of this study showed the effectiveness of blending PLA with PMMA, and its reinforcement with modified-CNC in order to develop a novel efficient nanocomposite packaging films.