Modified Cellulose Nanocrystals Enhanced the Compatibility Between PLA and PBAT to Prepare a Multifunctional Composite Film

Polylactic acid (PLA), Poly (butylene adipate-terephthalate) (PBAT) and Quaternary ammonium salt modified cellulose nanocrystals (SCNC) were used to prepare a multifunctional composite film using co-precipitation method. The addition of SCNC not only played the role of plasticizing, but also inhibited the individual aggregation of PBAT, which improve the compatibility between PLA and PBAT. The mechanical properties of the film were improved than that of PLA/PBAT films and the elongation at the break after adding 0.5%wtSCNC increases by 116.2% compared with PLA film. The addition of PBAT and SCNC significantly increases the functionality of PLA films. The water vapor transmission rate of the films decreased up by 74% compared with PLA and the migration rate of food simulant liquid decreased by about 80% after adding SCNC. In addition, the ultraviolet resistance of PLA/PBAT/SCNC composite film was significantly improved. PLA/PBAT/0.5wt%SCNC film showed the best light transmittance in the visible light range in different PLA/PBAT/SCNC films, and the UV transmittance at 380 nm was only 12.3% which was 14.3% of PLA. The multifunctional composite film produced by this work provided a new choice for the preparation of fully degradable packaging materials.Graphical Abstract