Alkyl Ketene Dimer Emulsions Stabilized by Layered Double Hydroxide Particles Modified with Glutamic Acid.

Alkyl ketene dimer (AKD) is commonly applied as oil-in-water emulsions in the papermaking industry. Herein a particle stabilized AKD emulsion was developed to avoid the adverse effect of surfactant, further improving the sizing performance and reducing the hydrolysis of AKD emulsions, where layered double hydroxide (LDH) particles were employed as a stabilizer of the AKD emulsions after being modified with glutamic acid (Glu). The success of the modification of LDH with Glu was evidenced by high-resolution transmission electron microscopy (HRTEM), zeta potential, Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) studies. Furthermore, the impact of the modification on the wettability of LDH was analyzed. It was found that the hydrophilic LDH particles became partially hydrophobic after being modified with Glu (at 1.5 mmol/g) and, thus, promoted the formation of emulsions with fine and uniform droplets that resisted creaming/coalescence formation. The adsorption of the Glu-modified LDH particles on the AKD droplet surface improved the emulsion stability, which was verified by fluorescent confocal laser scanning microscopy. Meanwhile, by using Glu-modified LDH nanoparticles, the storage stability of AKD emulsion and its sizing performance on paper were also improved. [ABSTRACT FROM AUTHOR]