www.nature.com/scientificreports/
Figure 10. Effect of CNF dosage on ( a ) transverse and ( b ) longitudinal tensile strength of paper.
Figure 11. SEM images of ( a ) base paper ( b ) PVA coated paper, and ( c ) PVA/CNF coated paper.
Ǥ Figure 11 shows the SEM images of base paper, PVA coated paper, and PVA/CNF coated paper. It can be observed from the Fig. 11a that the fibers of the base paper are crisscrossed, and there are a lot of gaps between the fibers. These gaps allow the liquid to penetrate the inside of the paper through capillary action, which is the main reason why the base paper does not have water and oil resistance. From the Fig. 11b,c we can observe that PVA and PVA/CNF coatings formed a smooth film on the surface of the paper, reducing the gap between fibers, thereby improving the ability of the paper to barrier oil/grease and water. This study showed that the basic chemical structures of BFs, EBFs and CNFs were similar and belong to the cellulose type I crystal. In addition, the prepared CNFs have the smallest size, with an average length of about 2.4 μm, an average diameter of about 28.7 nm, and a crystallinity of 63.63%. This study also showed that the oleophobicity, hydrophobicity, and tensile strength of the coated paper increased gradually with the increase of CNF dosage in the PVA/CNF coating solution. When the PVA/CNF coating weight was 2.0 g/m 2 and the CNF dosage was increased from 0.0% to 3.0%, the paper grease resistance grade was increased from 7 to 9, the Cobb value was decreased from 22.68 ± 0.29 g/m 2 to 18.37 ± 0.63 g/m 2 , the contact angle was increased from 67.82° to 93.56°, and the longitudinal and transverse tensile index were increased from 67.72 ± 0.21 N m/g and 37.63 ± 0.25 N m/g to 68.61 ± 0.55 N m/g and 40.71 ± 0.78 N m/g, respectively. Furthermore, with the increase of PVA/CNF coating amount, the hydrophobicity, oleophobicity and strength of PVA/CNF coated paper were improved. In summary, compared with the PVA coated paper, the hydrophobic and oleophobic properties of PVA/CNF coated paper are significantly improved, and the strength is maintained well. It is of great significance for the development of environmentally friendly oilproof packaging materials. All data generated or analysed during this study are included in this published article. Received: 17 July 2022; Accepted: 14 September 2022
Ƥ |
ǣȀȀǤȀͷͶǤͷͶ;ȀͺͷͻͿ;ǦͶǦͶͺͿͿǦ;
;
(2022) 12:16148 |
Vol:.(1234567890)
Made with FlippingBook - Online magazine maker