Alkenyl Succinic Anhydride Emulsion Research Articles

Encapsulation of alkenyl succinic anhydride oil droplets in emulsions: Preparation, characterization, stability properties and application in papermaking

This paper aimed to explore the influence of the guar and xanthan gum complex (GG/XG) on the physicochemical properties, microstructure, and sizing efficiency of alkenyl succinic anhydride (ASA) loaded emulsions. The centrifugal stability of the emulsions was measured using a Turbiscan equipment, the droplets morphology through an optical microscopy, the size of droplets and its distribution through a Mastersizer, and the sizing efficiency through the penetration method. Furthermore, Cryo-SEM and CLSM were used to elucidate the adsorption mechanism of polysaccharides at the ASA-water interface. When the concentration of GG/XG exceeded 0.35%, the ASA emulsions displayed excellent stability and low viscosity, and no water separation was observed even after high-speed centrifugation. By absorbing GG/XG at the oil-water interface, a dense interfacial film was formed, which blocked any interaction between the oil and water, thus hindering the hydrolysis of ASA. The sizing degree of the paper sized by ASA emulsion stored for 2 h was still higher than 88 s. By encapsulating ASA in emulsions that are stabilized exclusively by natural polysaccharides, the need for surfactants is eliminated, which in turn decreases the amount of foam present in the papermaking process, thus making it a more environmentally friendly production method.

Alkenyl Succinic Anhydride: The Question of Covalent Bonding and Chemistry Considerations for Better Sizing—Review

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.

Stabilization of the emulsion of Alkenyl Succinic Anhydride (ASA) in water using cellulose nanofibrils

Alkenyl Succinic Anhydride (ASA) is sizing agent that is applied as an aqueous emulsion during the papermaking process to improve paper’s hydrophobicity. However, its application becomes difficult as the emulsion quickly destabilizes due to the coalescence phenomenon and the high reactivity of ASA with water. In this work, we used cellulose nanofibrils (CNFs) to increase the stability of the ASA emulsion over time. Small amounts of CNFs added to the emulsion helps to increase its storage life by almost 3 times, by means of stabilizing the average droplet size and reducing the amount of hydrolyzed ASA. The time extension allows higher flexibility of the sizing processes. In this work, we identify the negative impact that the temperature and the presence of metal ions in water have on the quality on the optimal ASA emulsion, resulting in a reduction in their effects for both factors with the presence of cellulose nanofibrils.

Encapsulation of alkenylsuccinic anhydride oil droplets in Laponite nanoparticles modified by carbon nitride quantum dots: Enhancement of emulsion stability and paper sizing performance

Alkenylsuccinic Anhydride (ASA) is commonly applied as oil-in-water emulsions in papermaking industry. Herein, a particle stabilized ASA emulsion was developed for avoiding the adverse effect of surfactant, further improving the sizing performance and reducing the hydrolysis of ASA Pickering emulsions, where Laponite nanoparticles were employed as a stabilizer of the ASA Pickering emulsions after being modified with carbon nitride quantum dots. It was found that the hydrophilic Laponite particles became partially hydrophobic after being modified with CNQDs in dosage of 20–40 wt%, and thus promoted the formation of emulsions with fine and uniform droplets that resisted creaming/coalescence formation. The adsorption of the Laponite/CNQDs particles on the ASA droplet surface improved the emulsion stability, which was verified by fluorescent confocal laser scanning microscopy. Meanwhile, by using Laponite/CNQDs nanoparticles, the storage stability of ASA Pickering emulsion and its sizing performance on paper was also improved.

Polyacrylamide stabilized alkenyl succinic anhydride emulsion as sizing agent for various cellulosic pulps and fillers

Cellulosic fiber is hydrophilic in nature and making it hydrophobic represents a process called sizing in papermaking. Alkenyl succinic anhydride (ASA) sizing is dominating over other sizing processes due to its high reactivity and economy. The shelf life of conventionally used cationic starch (CS) stabilized ASA emulsion is 20−25 min. In our previous study, the ASA emulsion was found to be stable up to 4 h using anionic polyacrylamide (APAM) as stabilizer. Present communication was aimed to utilize, the APAM stabilized ASA emulsion with most commonly utilized cellulosic pulps (mixed hardwood, bagasse and recycled) and fillers to assist its commercial utilization in papermaking. APAM stabilized ASA emulsion facilitated back water utilization with improved sizing degree unlike CS based ASA emulsion. Lower amount of ASA sizing was required in bagasse pulp compared to other pulps which might be attributed to low crystallinity ratios and hydrogen bond energy.

Studies on ASA emulsion stabilized with anionic polyvinylamine and its evaluation for sizing of different types of paper furnishes

Low stability of cationic starch (CS) stabilized alkenyl succinic anhydride (ASA) emulsion is the main drawback of ASA sizing of paper to impart hydrophobicity. Present communication deals with the study of anionic polyvinylamine (APVAm) stabilized ASA emulsion at different process conditions viz. pH, temperature and pulps viz. mixed hardwood (MHW), bagasse (BBS), recycled (RCL) & fillers. APVAm stabilized ASA emulsion was found to be stable at higher pH and temperature. Sizing was better with BBS pulp followed by RCL and MHW pulps. It was evident from the crystallinity ratios and hydrogen bond energy that BBS pulp had the maximum amorphous region that was translated into lesser chemical requirement to attain same sizing followed by RCL and MHW pulps. The better sizing behaviour with lesser dosage of APVAm stabilized ASA emulsion was observed with unfilled and talc filled paper as compared to ground calcium carbonate and precipitated calcium carbonate filled paper.

Cationic starch and polyacrylamides for alkenyl succinic anhydride (ASA) emulsification for sizing of cellulosic fibers

Paper is composed of polysaccharides mainly cellulose and carbohydrates. The hydroxyl groups present in cellulose react with various substances added to fibrous slurry. Treating the cellulosic fibers chemically, which tends to develop the resistance to aqueous liquid absorption, is known as internal sizing of paper. The main internal alkaline sizing chemicals are alkyl ketene dimer and alkenyl succinic anhydride (ASA). In situ emulsification of ASA using cationic starch (CS) is conventionally practiced because of the low shelf life of ASA emulsion. In the present communication polyacrylamides (PAMs) have been used as an alternative chemical to cationic starch at very low dosages than cationic starch and varying ratios of ASA to polyacrylamides to stabilize the ASA droplets. The colloidal stability of ASA emulsions was measured in terms of particle size distribution, sizing performance, pH and percent hydrolysis of ASA with the passage of time. The ASA emulsions prepared with PAMs at very low dosage were observed with superior colloidal stability and sizing behaviour than the CS stabilized emulsion.

Sizing performance of alkenyl succinic anhydride (ASA) emulsion stabilized by polyvinylamine macromolecules

It is well known that alkenyl succinic anhydride (ASA), an alkaline sizing agent, when applied to cellulosic fibers will impart a resistance to the absorption of water. High reactivity of ASA to cellulosic fiber compared to that of alkyl ketene dimer (AKD) is the main advantage of ASA sizing. However, there are some drawbacks associated with the ASA sizing viz. poor stability of ASA emulsion and formation of stickies and deposits as a result of hydrolyzed ASA. Present study deals with the stability of ASA emulsions prepared by using synthetic vinylamine polymers of different colloidal charge as alternate to conventionally used cationic starch and sizing performance using mixed hardwood kraft pulp furnish. The better colloidal stability and sizing performance with polyvinylamines compared to cationic starch was due to the coverage of the ASA droplets with polyvinylamines which extends in to the continuous phase of ASA emulsion. Emulsion stability was achieved even with low dosage of vinylamine polymer.

Stabilizing alkenyl succinic anhydride (ASA) emulsions with starch nanocrystals and fluorescent carbon dots

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 H2SO4 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.

Preparation of starch and laponite co-stabilized alkenyl succinic anhydride emulsions for paper sizing

ABSTRACTStable 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.

Comparison of alkenyl succinic anhydride emulsions stabilized by laponite modified with ethylamine, diethylamine and triethylamine

ABSTRACTThe modifications of laponite particles with three short amines, that is, ethylamine, diethylamine and triethylamine, were compared and the amine-modified laponites were used to stabilize alkenyl succinic anhydride emulsions. The results show that the emulsion stability can be improved while the emulsion droplet size can be reduced by using the amines to modify laponite particles. Among the three amines, the diethylamine exerts the largest while the triethylamine exerts the smallest effects on the zeta potential of laponite, the turbidity of laponite aqueous dispersion and the emulsion stability and morphology. The emulsion with the smallest droplet size shows the highest sizing performance.

Improving Stability and Sizing Performance of Alkenylsuccinic Anhydride (ASA) Emulsion by Using Melamine-Modified Laponite Particles as Emulsion Stabilizer

Alkenylsuccinic anhydride (ASA) is commonly applied as oil-in-water (o/w) emulsions in the papermaking industry. Herein Laponite mineral nanoparticles were employed as a stabilizer of the ASA emulsions after being modified with melamine just before emulsion preparation. The emulsion was prepared by homogenizing the mixture of ASA and melamine-modified Laponite aqueous dispersion. The modification of melamine on the Laponite was characterized by infrared spectroscopy and X-ray diffraction, whereas the impacts of the modification on the morphology, wettability and ζ-potential of the Laponite, as well as the interfacial tension between ASA and Laponite aqueous dispersion, were also analyzed. It is found that the adsorption of melamine on Laponite particles neither causes the aggregation nor significantly changes the charge properties of the Laponite particles. However, the adsorption of melamine can significantly increase the wettability of Laponite by the ASA liquid, and adequately lower the apparent interfacial tension between ASA and Laponite aqueous dispersion when the melamine-to-Laponite mass ratio is less than 3%. This results in an improvement in emulsion stability, a reduction in emulsion droplet size and an enhancement in the sizing performance of the ASA emulsion when the emulsion is stabilized by melamine-modified Laponite particles. The ASA emulsion with the smallest droplet size and best sizing performance is produced at a melamine-to-Laponite mass ratio of 3%. By monitoring the variations of the emulsion with time, it is discovered that the modification of Laponite with melamine can restrain the growth of emulsion droplets and the hydrolytic action of ASA substantially, thus decreasing the loss in sizing performance of the ASA emulsion with time. This is particularly important for the wide application of ASA emulsions in the papermaking industry.

ASA-in-water emulsions stabilized by laponite nanoparticles modified with tetramethylammonium chloride

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.

Stability and efficiency improvement of ASA in internal sizing of cellulosic paper by using cationically modified cellulose nanocrystals

Alkenyl succinic anhydride (ASA) is a reactive sizing agent that can impart good water repellence to paper by decreasing the wettability of the cellulose fibers. However, ASA can undergo hydrolysis, which is detrimental to the ASA sizing efficiency. In order to improve the ASA emulsion stability and ASA sizing efficiency, we used cationically modified cellulose nanocrystals (CNCs) to stabilize the cationic starch-emulsified ASA. Transmission electron microscope observation revealed that ASA droplets were well shielded by both the cationic CNCs and cationic starch, which may be responsible for the improved stabilization of ASA. The Hercules size test sizing degree, contact angle and particle size measurements demonstrated that cationic CNCs–ASA sized paper exhibited improved results in comparison with the control (without cationic CNCs under otherwise the same conditions). Furthermore, the resulting cationic CNCs–ASA system can improve the tensile index and burst index of the sized paper.

Stabilization of ASA-in-water emulsions by Laponite modified with alanine

Alkenyl succinic anhydride (ASA) is an oily paper sizing agent that is generally introduced into the paper manufacturing system as an ASA-in-water emulsion. In this paper, ASA-in-water emulsions are prepared by homogenizing the mixture of ASA and aqueous dispersion of Laponite modified with alanine. The modification of Laponite with alanine reduces the emulsion droplet size, and enhances the emulsion stability against coalescence due to lowering the interfacial tension between ASA and water containing Laponite and improving the affinity of Laponite particles toward ASA. Infrared spectrum analysis indicates that the adsorption of alanine on the Laponite particles retards the hydrolysis of ASA when the alanine-modified particles are employed to stabilize ASA emulsions. Meanwhile, the sizing efficiency of the as-prepared ASA emulsion is also improved by the modification of Laponite with alanine, and more dependent on emulsion droplet size than on the hydrolysis of ASA.

Using urea to improve stability, sizing performance and hydrolysis resistance of ASA emulsion stabilized by Laponite

As a paper sizing agent, alkenyl succinic anhydride (ASA) emulsion is generally stabilized by cationic starch or synthetic polymer. In this paper, Laponite and urea were employed as particle stabilizer and the modifier of Laponite particle, respectively, to stabilize the ASA emulsion. It is founded that the presence of urea enhances the stability of ASA emulsion, reduces the emulsion droplet size, resulting in improved sizing performance of the ASA emulsion. ASA emulsion with smallest droplet size and best sizing performance on BCTMP is obtained at the urea dosage of 50wt% based on Laponite. The sizing test of ASA emulsion and the infrared spectrum analysis of ASA substances separated from ASA emulsions with different storage time indicate that the introduction of urea in emulsification process can restrain the hydrolytic action of ASA effectively and sustain the sizing performance of ASA emulsion even two hours after its preparation. This is a possible way to solve the problem that paper mills have always encountered: the too rapid hydrolysis of ASA emulsion.

Phase inversion of TiO2 nanoparticle stabilized emulsions of alkenyl succinic anhydride

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.

Using cationic polymers to improve alkenyl succinic anhydride (ASA) sizing efficiency in high-yield pulp containing furnish

High-yield pulp (HYP) such as bleached chemi-thermo-mechanical pulp (BCTMP) from aspen wood, is now being used in the production of high-quality fine papers, and this is particularly true in China. In this study, the effect of using cationic polymers such as poly-aluminum chloride (PAC), polyethylenimine (PEI), cationic polyacrylamide (CPAM), and poly-(diallyldimethylammonium chloride) (PDADMAC) on Alkenyl Succinic Anhydride (ASA) sizing efficiency in HYP-containing pulp furnish was investigated. The results showed that the addition of only ASA emulsion to the HYP-containing furnish, without any cationic additives, did not yield an appreciable degree of sizing in the paper sheet. PAC (or alum) could improve the ASA sizing efficiency. PEI, PDADMAC, CPAM, and NaHCO3 all improved ASA sizing efficiency in the presence of PAC. The charge density of PEI was important for improving the ASA sizing performance. Also, the sequence of adding the cationic polymer affected the ASA sizing performance.

Roles of short amine in preparation and sizing performance of partly hydrolyzed ASA emulsion stabilized by Laponite particles

Alkenyl succinic anhydride (ASA) is an internal sizing agent used to hydrophobize paper and paperboard in paper making process. Partly hydrolyzed ASA (hereinafter referred to as PH-ASA) emulsions can be stabilized by Laponite and short amines such as ethylamine, n-propylamine and n-butylamine. It is found that the short amines may improve the affinity of Laponite particles to PH-ASA, favoring PH-ASA emulsification, forming emulsion of high stability and small droplets. It is further observed that the sizing development of the PH-ASA on bleached chemi-mechanical pulp (BCTMP) is promoted when aluminum sulfate is added. Amine with longer carbon chain is more efficient both in promoting PH-ASA emulsification and in its sizing process. The amine molecules adsorbed on Laponite are more effective in stabilizing PH-ASA emulsions while the free amine in the dispersion work more efficiently in promoting sizing performance through a mechanism of accelerating the reaction between hydrolyzed ASA and aluminum sulfate. However, the PH-ASA emulsions lose most of their sizing effect by hydrolysis within 60 min.

Retention behavior of alkenyl succinic anhydride size on handsheets.

Handsheets were prepared with alkenyl succinic anhydride (ASA) under various conditions, and retention behavior of ASA on the handsheets was studied. The addition of polyamideamine-epichlorohydrin resin (PAE) and/or aluminum sulfate to pulp suspensions resulted in higher sizing level together with greater ASA content of the handsheets prepared thereof, compared with the result for handsheets prepared without PAE. At the same ASA content, the handsheets prepared by the ASA-aluminum sulfate system had higher sizing level than those prepared by the ASA-PAE system. ζ-Potential measurement supported the idea that ASA emulsion particles had amphoteric surface charges in pulp suspensions, owing to hydrolyzed ASA molecules formed on size emulsion particles by hydrolysis. Cationic compounds such as PAE and aluminum sulfate can, therefore, interact with anionic sites of both ASA emulsion particles and cellulose, and higher size retention can be achieved by these electrostatic interactions in pulp suspensions.