Ductile nanocellulose-based films with high stretchability and tear resistance

Hybrid composite films of nanofibrillated cellulose (NFC), cationic hydroxyethylcellulose (CHEC) and glycerol were prepared via solution blending. NFC adopted a fibrillar structure, being coated with the CHEC moieties. Ionic interactions between NFC and CHEC were present, as confirmed by FTIR, leading to enhanced strength, moduli and work-to-break values. Simultaneously, segments of non-cationic HEC worked in tandem with glycerol to lubricate the cellulose nanofibrils, yielding maximum strain-at-break values of 141%. The NFC-CHEC-glycerol films were subsequently coated with a 4.5-6 mu m layer of poly(propylene carbonate) (PPC), microscopy confirming effective coating of NFC at the composite-coating layer boundary. The hydrophobic nature of PPC enhanced water stability for acute time periods and increased contact angle values. Film strength and toughness was also enhanced by PPC, indicative of its reinforcing ability. The hybrid composites highlight the ability to prepare extremely ductile cellulose-based films, with the aforementioned materials being amongst the most ductile cellulose-based and/or cellulose-majority films documented. (C) 2015 Elsevier Ltd. All rights reserved.