Synthesis of surface quaternized cellulose nanofibrils for high-performance antibacterial composite films

Cellulose nanofibrils (CNF) are promising nanomaterials with considerable potential in packaging materials due to their excellent mechanical properties and sustainability. However, the limited functionality of CNF restricts their applications in functional packaging materials. Herein, a series of surface quaternized CNF (CCNF-Q n ) with tunable alkyl chain lengths (C 8 –C 16 ) were synthesized by first surface chloroacetylation using vinyl chloroacetate, and then quaternization with tertiary amines. The CCNF-Q n were comparatively characterized and the quaternary ammonium groups were successfully introduced onto the surface of the CNF. The XPS results revealed that the N/C atomic ratios of the CCNF-Q n range from 0.016 to 0.022. The CCNF-Q n were further utilized to improve the mechanical and antibacterial properties of the polyvinyl alcohol (PVA) films. At 5.0 wt% CCNF-Q n incorporation, the tensile strength and elongation at break of the composite film reached 53.7 MPa and 229.7 %, respectively. The composite films with longer alkyl chains achieved nearly 100 % inhibition against Escherichia coli and Staphylococcus aureus . This work provides a new route for the synthesis of surface quaternized CNF, which show excellent antibacterial performance and have promising application prospects in high-performance packaging materials.