Recyclable cellulose nanofibers reinforced poly (vinyl alcohol) films with high mechanical strength and water resistance.

Sargasso cellulose nanofibers (CNFs) and polyvinyl alcohol (PVA) components were composed to generate novel KCNF/PVA films by a simple and benign crosslinking strategy. Sargasso CNFs are a potential reinforcement material due to its extremely long length (15-20 μm) and natural nanostructure. The low water resistance of PVA limits their use in humid and watery environments. However, the chemical cross-linking between sargasso CNFs and PVA consumes a large number of hydrophilic hydroxyl groups, the resulting KCNF/PVA films exhibited outstanding water resistance (water contact angle 119°). Especially, the wet strength of KCNF/PVA films (50 MPa) was raised by 92 times when compared to that of pristine PVA films (0.54 MPa). Furthermore, these KCNF/PVA films could be dissolved and recycled easily. The regenerated films also show outstanding mechanical performance.
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