Effects of surfactants on the wettability of sodium propionate aqueous deacidification agent

To address the challenges of difficulty and low penetration speed of aqueous deacidification agents in paper, we aimed to enhance the wetting performance of these agents by incorporating a surfactant. We selected four surfactants for our study: anionic sodium dodecyl benzene sulfonate (SDBS), cationic cetyltrimethylammonium bromide (CTAB), nonionic polysorbate-80 (TW80), and polyether-modified trisiloxane (TRSE). The wetting properties of these surfactants on sodium propionate aqueous deacidification agent, the alkali stability of the solution, and the effects of moist heat aging on paper durability were explored. The results demonstrated that TRSE exhibited superior performance compared to the other three surfactants, effectively reducing the surface tension of sodium propionate solution to 21.02 mN/m. In alkaline conditions with a pH range of 8.00–10.00, the surface tension of SDBS, CTAB, and TW80 solutions remained stable for 30 days. Similarly, under weakly alkaline conditions with a pH value below 9, the surface tension of TRSE solutions exhibited stability. It should be noted that SDBS accelerated the decline of paper tensile index and whiteness during the heat and humidity aging process; at the same time, CTAB, TW80, and TRSE had no noticeable adverse effects on paper aging resistance.