Search

Alkenyl Succinic Anhydride (ASA) is a sizing agent used in papermaking to increase the water repellency of paper. Almost 60 years after the introduction of the chemical in papermaking, scientists still have differing views on how ASA interacts with cellulose. Several experiments were conducted to bring more clarity to the ASA sizing mechanism, especially on the contentious question of ASA-cellulose covalent bonding or the esterification reaction between ASA and cellulose during papermaking. Herein, research papers and patents, including experiments and results, from the 1960s to 2020 were reviewed. Our investigation revealed that the ester bond formation between ASA and cellulose is insignificant and is not a prerequisite for sizing effectiveness; the main ASA-related material found in sized paper is hydrolyzed ASA or both hydrolyzed ASA and ASA salt. In addition, ASA emulsion stability and ASA emulsion retention are important for sizing efficiency improvement. [ABSTRACT FROM AUTHOR]

Biodegradable colloidal particle materials are becoming attractive candidates as eco-friendly chemical additives in the low-carbon economy era. However, developing cheap, stable, and efficient paper-sizing agents is still a challenging issue for both the paper-making academic community and industry. Here, an easy-fabricating, stable, and high-performance alkenyl succinic anhydride (ASA) paper-sizing emulsion that is stabilized by lauric arginate (LAE)/cellulose nanocrystals (CNCs) nanorods is developed. Furthermore, the partial hydrophobization between ASA and LAE/CNCs can be adjusted due to the partial hydrophobization between ASA and LAE/CNC nanorods, resulting in improved stability of the ASA-sizing emulsion. This novel paper-sizing emulsion is shown to have a small droplet size (0.8 μm), high hydrolysis resistance, and a high paper-sizing degree (300 s) along with a remarkable hydrophobicity contact angle of 110° for long-term storage. This work enables the realization of an interfacial self-assembled Pickering-stabilizer, which leads to an environmentally friendly, pervasive and cost-effective emulsification technique for next-generation paper-sizing additives. [ABSTRACT FROM AUTHOR]

Stabilizing alkenyl succinic anhydride (ASA) emulsions using fine particles instead of cationic starch have attracted much attention in recent years. Herein, starch nanocrystals (SNCs) made from maize starch by H 2 SO 4 hydrolysis were used to co-stabilize ASA emulsions with fluorescent carbon dots (CDs) made hydrothermally from gelatin. The introduction of CDs can significantly enhance the stability and reduce the droplet size of SNC-stabilized ASA-in-water emulsions. Consequently, the sizing performance of the SNC-stabilized ASA emulsion is significantly improved by increasing the CD-to-SNC mass ratio. SNC and CD co-stabilized ASA emulsions show much better sizing performance than starch and CD co-stabilized ASA emulsions, achieving their best sizing performance at a CD-to-SNC mass ratio of 80%. Meanwhile, the morphology of SNC/starch and CD co-stabilized ASA emulsions can be traced under UV excitation. [ABSTRACT FROM AUTHOR]

Stable alkenyl succinic anhydride (ASA) emulsions with approximately 25% of ASA were prepared by using native maize starch and laponite particles as stabilizers. The morphology, sizing performance, and storage stability of the as-prepared ASA emulsions were evaluated. It was surprisingly found that the introduction of laponite particles could significantly improve the emulsion stability, reduce the emulsion droplet size, and enhance the sizing performance, while the occurrence of native maize starch depresses the deterioration of the ASA emulsion in sizing performance with increasing emulsion storage time. [ABSTRACT FROM PUBLISHER]

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]

Alkenyl succinic anhydride (ASA) is a widely used paper sizing agent that is applied in the form of oil-in-water (o/w) emulsions in order to impart a water-resistant character to the resulting paper. To obtain stable o/w emulsions of ASA, laponite, a highly hydrophilic synthetic clay, was selected as the stabilizer after it had been modified with tetramethylammonium chloride (TMAC), a quaternary ammonium salt with the shortest possible hydrocarbon groups. It was found that the TMAC moderately neutralized the negative charges of laponite particles, lowered the apparent viscosity, but enhanced the turbidity of laponite aqueous dispersion by enhancing the hydrophobicity of the laponite particles, favoring adsorption of laponite particles on the ASA-water interface. Meanwhile, the TMAC significantly decreased the interfacial tension between ASA and water/aqueous laponite dispersion, promoting the formation of an emulsion with small droplets. When the added amount of TMAC reached 1wt% based on laponite, the as-prepared ASA emulsion had small droplet size, low viscosity and uniform droplet size distribution, and exhibited good creaming/coalescence stability. By using TMAC to modify laponite nanoparticles, the hydrolysis stability and sizing performance of ASA emulsion were also improved. [ABSTRACT FROM AUTHOR]

Abstract: Alkenyl succinic anhydride (ASA) is a viscous polar oil, typically used as a paper sizing agent after being emulsified. ASA and water emulsions stabilized by TiO2 nanoparticles were prepared by adding the aqueous phase to the oil phase. Catastrophic phase inversion from w/o to o/w or w/o/w has been investigated by monitoring the variation of emulsion conductivity with water mass fraction at different homogenization speeds, initial particle locations and particle concentrations. When initially dispersed in water, TiO2 nanoparticles carry positive charge and interact with hydrolyzed ASA at the water–ASA interface. The particles are thus hydrophobically modified, resulting in phase inversion from w/o to w/o/w at higher water mass fraction, while for particles originating in ASA, the phase inverts from w/o to o/w at a lower water mass fraction. Higher homogenization speed and lower particle concentration induce phase inversion at lower water mass fractions. In addition, variations in the phase inversion point caused by the homogenization speed and particle concentration are magnified when the particles originate in water. Similar to non-ionic surfactant-stabilized emulsions prepared by a catastrophic emulsification process, the particle-stabilized emulsions containing ASA exhibit a diminished drop size when approaching the water mass fraction at which phase inversion occurs. Emulsions with the particles initially dispersed in ASA have a slightly smaller drop size than those with particles initially dispersed in water. In addition, the drop size near the phase inversion point did not obviously change with particle concentration. [Copyright &y& Elsevier]