Use of cellulose nanofibers to improve hydrophobic and oleophobic properties for polyvinyl alcohol coated paper

Abstract

The effect of the composite coating containing a mixture of polyvinyl alcohol (PVA) and cellulose nanofibers (CNFs) prepared from bamboo pulp on the hydrophobic, oleophobic and strength properties of paper was investigated. The results showed that the size of bamboo fibers (BFs) decreased significantly and the crystallinity increased significantly after biological enzyme treatment. The average length of CNFs obtained by high pressure homogenization was about 2.4 µm, the diameter was about 28.7 nm, and the crystallinity was 63.63%. When the coating weight of PVA/CNF was 2.0 g/m2 and the CNF dosage was increased from 0.0–3.0%, the paper grease resistance grade was increased from 7 to 9, the Cobb value was decreased from 22.68 g/m2 to 18.37 g/m2, the contact angle was increased from 67.82° to 93.56°, and the longitudinal and transverse tensile index were increased from 67.72 N∙m/g and 37.63 N∙m/g to 68.61 N∙m/g and 40.71 N∙m/g, respectively. When the CNF dosage was 3.0% and the coating weight of PVA/CNF was increased to 4.0 g/m2, the grease resistance grade of the paper reached 12, the Cobb value was 21.80 g/m2, and the longitudinal and transverse tensile indices were 72.11 N∙m/g and 42.58 N∙m/g, respectively. Overall, the addition of CNFs to the PVA coating significantly improves the oleophobic property of the coated paper, and the hydrophobicity and tensile strength are well maintained.