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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]

Alkenyl succinic anhydride (ASA) is a popular paper-siz ing agent that is generally added to papermaking systems as an aq ueous emulsion. Herein, we reviewed the recent work focusing on ASA emulsions stabiliz ed by solid particles. Solid particle-stabiliz ed ASA emulsions generally possess high ASA content and exhibit good siz ing performance. The particles that have been used to stabiliz e ASA emulsions typically include montmorillonite, laponite, alumina, TiO2 , Fe3 O4, polyaluminum sulfate (PAS), and cellulose nanocrystals (CNCs). Montmorillonite is the first extensively studied particle stabilizer for ASA emulsions. Laponite is undoubtedly the most competent particle stabiliz er for preparing ASA emulsions with high siz ing efficiency. Montmorillonite and laponite can be used individually as stabiliz ers after modification or as co-stabiliz ers with other particles or polymers. TiO2, alumina, PAS, and CNCs are commonly used as stabiliz ers either individually or with other particles [ABSTRACT FROM AUTHOR]

Processing convenience and paper-sizing flexibility frequently require the delivery of alkenylsuccinic anhydride oil as emulsion. The shelf life of the oil is achieved kinetically, in most cases via the addition of surfactants such as cationic starch or a synthetic polymer, which are the subject of increasing scrutiny with regard to their environmental impact. The modification of montmorillonite nanoparticle with sodium fluoride was found to decrease the interfacial tension between dodecenylsuccinic anhydride (DDSA) and aqueous dispersion and to change the wettability of montmorillonite, which benefits the preparation of DDSA-in-water emulsions with enhanced stability, small droplet size, and improved hydrolysis resistance. Adjusting the pH and particle concentration of aqueous solution effectively improved the stability of DDSA emulsion. Catastrophic phase inversion from w/o (water-in-oil) to o/w (oil-in-water) was investigated by monitoring the variation of emulsion conductivity with increasing oil volume fraction. Evidence of the transition from loose particle-film to compact particle shell upon introduction of salt was found, as predicted theoretically for charged particles adsorbed on interfaces. Particulate interfacial films built by SFMMT nanoparticles protected DDSA droplets from aggregation and formed a honeycomb structure. Salt in the DDSA emulsification process restrained the hydrolytic action of DDSA effectively and sustained the sizing performance of DDSA even 5 h after the emulsion preparation. [ABSTRACT FROM AUTHOR]

Recently,carbon dots (CDs) have drawn much attention as evidencedby their incorporation into many branches of science and engineering.Herein, a further unique application is elucidated: CDs that are synthesizedby the hydrothermal treatment of gelatin for a dual functionalityas expressed in costabilization of particle-based emulsions and theirconcomitant role as fluorescent probes. CDs either with or withoutgelatin matrixes induce the aggregation of Laponite particles. Theintroduction of CDs thus enhanced the stability of Laponite-stabilizedemulsions and promoted the formation of multiple emulsions and emulsionswith fine and uniform droplets when the CD-to-Laponite mass ratiowas less than 45% and exceeded 60%, respectively. However, CDs withoutgelatin matrixes show slightly higher efficiency than CDs within gelatinmatrixes for the costabilization of emulsions. CDs also costabilizedemulsions with Laponite to allow the distribution of Laponite particlesto be traced and the emulsion profiled under UV. [ABSTRACT FROM AUTHOR]