Preparation of 4,4′-diaminostilbene-2,2′-disulfonic acid derivative/ PVA/ LDHs composite fluorescent brightener and performances on paper surface

In order to improve the anti-aging property and surface strength of high-yield-paper (HYP), a novel composite fluorescent brighter (PFB/PVA/LDH) was successfully synthesized via hydrothermal reaction with 4,4′-diaminostilbene-2,2′-disulfonic acid derivative (PFB), polyvinyl alcohol (PVA) and layered double hydroxides (LDH) as raw materials in this study. The introduction of LDH can effectively shield the ultraviolet to improve the anti-aging performance on one hand, and PVA will enhance the strength of paper though formation of thin film on the other hand. The anti-yellowing property of the as-prepared PFB/PVA/LDH was remarkably excellent than that of pure PFB for the HYP paper. After 70 h aging, the brightness of paper sheets coated with PFB/PVA/LDH is still reached to 91.24 ISO%. Moreover, the composite brighter could form a thin film in the surface of paper sheets to improve its surface strength and smoothness. Compared with blank paper sheets, the surface strength and smoothness of paper sheets treated with 0.4 g m−2 of PFB/PVA/LDH were increased 2.11 m s−1 and 56.8 s, respectively. Based on the characterization and results analysis, it can be inferred that the PFB/PVA/LDH composite can not only improve the paper's brightness as a fluorescent brightener and anti-aging agent, but also increase its surface strength as a surface sizing agent.