www.nature.com/scientificreports/
Type PVA
pH
Apparent viscosity [cP] @ 200 rpm
6.87 6.92
998 ± 15
PVA/CNF
± 37
Table 3. Coating properties. Note: The concentration of PVA was 10%, and the CNF dosage was 3.0% (relative to the mass of PVA).
Figure 6. Images of kit testing of ( a ) base paper, ( b ) PVA coated paper, and ( c ) PVA/CNF coated paper.
Figure 7. Effect of CNF dosage on grease resistance of paper.
ance performance was further improved with the addition of CNFs in PVA coating. When the CNF dosage was 3.0%, the grease resistance grade of the coated paper reached the highest value, which was grade 9, and then it was unchanged with the further increase of CNF dosage. When the coating weight was 4.0 g/m 2 and the CNF dosage was 1.0%, the grease resistance grade of the PVA/CNF coated paper reached the highest level, which was grade 12. Compared with base paper, the coated paper had better oil and grease resistance, which was due to the porous structure of base paper, that the liquid was easily absorbed and penetrated. After coating, the surface of the paper was covered with a continuous film, which greatly reduced the void size of paper, thereby reducing the penetra- tion rate of liquids 52 . Furthermore, the addition of CNFs to the coating further improved the grease resistance of the coated paper, which was due to the CNFs increased the compactness of the coated film, preventing oil and grease from penetrating into the paper inside 11 . Ǥ As shown in Fig. 8, with the CNF dosage increased from 0.0% to 3.0%, the Cobb value of the coated paper gradually decreased, indicating that the hydrophobicity gradually improved. When the CNF dosage exceeded 3.0%, the Cobb value began to increase, so the hydrophobicity began
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(2022) 12:16148 |
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