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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]

The paper proposes a method of infrared spectroscopy for objective control of the adhesive composition in the production of paper. For sizing paper, in order to increase mechanical strength and reduce water absorption, water-repellent materials are used. One of the most effective and used water-repellent material is ordinary pine resin rosin which is in short supply for the Republic of Uzbekistan. The paper investigates the properties of a new adhesive based on rosin from cherry resin for use in mass sizing in order to expand the range of sizing agents and reduce the share of imported components in the structure of local paper production. Infrared spectroscopy was used to identify the rosin-based glue from the resin of the cherry tree. The built-in device with a diamond crystal of the universal and compact Thermo Scientific Nicolet iS50 IR Fourier spectrometer made it possible to register spectra in the mid and far IR ranges up to 100 cm–1. The efficiency of sizing paper samples was studied by standard methods and evaluated by the following properties: density, tensile strength at stretching on a tensile machine, surface absorbency with one-sided wetting. Infrared spectra revealed the identity of the sizing agent from the resin of the cherry tree to the glue from the pine resin, taken for comparison, because their chemical composition is the same. A comparative analysis of the mechanical and surface properties of paper samples confirmed the possibility of using the studied sizing agent, since the obtained values are close to each other, while it is advisable to add in the range from 1 to 1.5 g per 100 g of dry cellulose raw materials. The use of infrared spectroscopy for express analysis of the composition of the sizing agent is promising, since it becomes possible to control the technological process and create glued types of paper products with desired properties that ensure print quality without loss of fine image details.

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.

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]

In this study, a novel cellulose nanocrystal/metal-organic framework composite (MC) was developed as a stabilizer for alkenyl succinic anhydride (ASA) Pickering emulsions, demonstrating remarkable sizing performance and antimicrobial properties for advanced food packaging applications. The MCs exhibited superior emulsion stabilization capabilities compared to pure metal-organic frameworks, with the optimum MC concentration identified as 1.0 wt% CNC. The hydrophobicity of the sizing paper was found to be enhanced with increasing CNC content. The MC-ASA sized paper demonstrated commendable storage stability, robust gas adsorption, and resistance to water vapor or water droplets. The MCs-ASA sized paper showed excellent food preservation efficacy, maintaining the freshness of strawberries for up to seven days, compared to ASA-sized paper without MCs. The antimicrobial assays targeting Escherichia coli and Staphylococcus aureus highlighted the intrinsic antimicrobial properties of the MCs, contributing to the extended freshness of the encased strawberries. The water vapor barrier efficacy and water retention capabilities of MCs-ASA sized paper were found to be superior to those of the paper without MCs, emphasizing the potential of the developed composite as an innovative and effective food packaging solution. This study offers valuable insights into the synthesis and implementation of CNC/MOF composite particles for versatile applications in food packaging, water-resistant materials, and environmental protection. [Display omitted] • CNC/MOF composites boost ASA Pickering emulsions' sizing performance. • MCs elevate hydrophobicity, gas adsorption, and sizing paper stability. • MCs-ASA paper extends strawberry freshness to 7 days in food packaging. • Research paves way for sustainable, eco-friendly advanced packaging solutions. [ABSTRACT FROM AUTHOR]

Sum frequency generation vibrational spectroscopy (SFS) was employed to study the alkyl ketene dimer (AKD) sizing mechanism employed in the papermaking industry for hydrophobization of cellulose. The AKD was spun coat onto model cellulose films, which resulted in ≈ 2.6 nm thick AKD layers. The chain orientation of AKD molecules during the sizing process was measured at different temperatures. It was demonstrated that the chain orientation and conformation of AKD do not correlate with observed changes in sizing. The distribution of AKD molecules on model cellulose surfaces as a function of time and temperature was imaged via fluorescence microscopy to complement SFS measurements. It was concluded that the distribution of AKD plays a major role in the sizing effect. [ABSTRACT FROM AUTHOR]

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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.

The charge density of cellulose fibers is a key parameter in the papermaking systems, and this is particularly true for the Alkyl Ketene Dimer (AKD) paper sizing. Zeta potential and cationic demand are often used to characterize these charges. Generally, a similar sizing performance would be obtained when the fibers with similar morphology and charge characteristics are used. However, in a mill trial, it was shown that three bleached birch pulp samples, with similar fiber morphology, and zeta potential, had different Alkyl Ketence Dimer (AKD) sizing behaviors. In this study, the surface charges of these pulp samples, measured using the poly electrolyte titration methods, were investigated. The results showed that lower sizing efficiency of fibers were due to their lower surface charges. It was concluded that the direct measurement of surface charge of cellulose fibers can be more appropriate to evaluate the AKD paper sizing efficiency. [ABSTRACT FROM AUTHOR]

Superhydrophobic paper with remarkable durability is of considerable interest for its practical applications. In this study, a scalable, inexpensive, and universal surface sizing technique was implemented to prepare superhydrophobic paper with enhanced durability. A thin layer of starch-based composite, acting as a bio-binder, was first coated onto the paper surface by a sophisticated manufacturing technique called surface sizing, immediately followed by a spray coating of hexamethyl disilazane treated silica nanoparticles (HMDS-SiNPs) dispersed in ethanol on the surface of the wet starch-coated sheet, and the dual layers dried at the same time. Consequently, durable superhydrophobic paper with bi-layer structure was obtained after air drying. The as-prepared superhydrophobic paper not only exhibited a self-cleaning behavior, but also presented an enhanced durability against scratching, bending/deformation, as well as moisture. The universal surface sizing of starch-based composites may pave the way for the up-scaled and cost-effective production of durable superhydrophobic paper. [ABSTRACT FROM AUTHOR]

Alkyl ketene dimmer (AKD) is widely used in papermaking industry, which is applied in form of o/w emulsion to increase paper water-resistance. In this paper, AKD-in-water emulsions were prepared by monosodium glutamate (MSG)-modified laponite. The aggregation, surface charge, and hydrophobicity of the laponite particles in aqueous dispersion were changed by the MSG and the properties of the as-prepared emulsions were varied correspondingly. When the MSG concentration is 2 mmol/g, AKD emulsion with small droplet size, high storage stability, and high sizing efficiency is obtained. The morphology, droplet diameter and distribution, storage stability and sizing efficiency of the AKD-in-water emulsion were investigated. [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]

• Novel method of measuring the uniformity of liquid penetration through fibrous porous materials was proposed. • Texture entropy and contrast were taken into account in the proposed method. • Correlations between the dynamics of liquid penetration and the examined texture parameters were found. • New parameters were introduced for better evaluation of the nature of the liquid flow through the porous material structure. The interaction of liquids with materials is an important factor influencing many technological processes and describing the quality of the material itself. However, characterization of the wetting and penetration of liquids phenomena through the materials of heterogeneous structure is a very difficult task. Paper is an example of such material. Paper sizing is one of the most important operations in paper technology. Its purpose is to reduce the wettability of the paper. The aim of the present study was to evaluate the suitability of the texture analysis to assess the uniformity of liquid penetration through the paper structure in terms of the degree of the paper sizing. As a result of the research, a new method of measuring was proposed based on dynamic changes in their texture parameters. For this purpose, such texture parameters as entropy and contrast were used. Characteristic points were determined on the curves of the dynamic changes of both parameters. It was proved that there is a correlation between the dynamics of liquid penetration through the paper structure and the examined texture parameters. It was found that the maximum value of entropy and contrast, the time of reaching both values, the points of inflection of the curves during their decrease, and the times by which these points were reached can be useful parameters that provide information about the nature of the liquid flow through the porous material structure. [ABSTRACT FROM AUTHOR]

The folded paper-size illusion is as easy to demonstrate as it is powerful in generating insights into perceptual processing: First take two A4 sheets of paper, one original sized, another halved by folding, then compare them in terms of area size by centering the halved sheet on the center of the original one! We perceive the larger sheet as far less than double (i.e., 100%) the size of the small one, typically only being about two thirds larger--this illusion is preserved by rotating the inner sheet and even by aligning it to one or two sides, but is dissolved by aligning both sheets to three sides, here documented by 88 participants' data. A potential explanation might be the general incapability of accurately comparing more than one geometrical dimension at once--in everyday life, we solve this perceptual-cognitive bottleneck by reducing the complexity of such a task via aligning parts with same lengths. [ABSTRACT FROM AUTHOR]

Cationic rosin has many uses in papermaking; however, its performance as an internal sizing agent differs depending on the circumstance, especially in the recycling of pulps. In this study, a comprehensive laboratory approach was used to investigate the process variables affecting the cationic rosin application in the paper recycling process. In this respect, four levels of alum (0.5, 1.0, 1.5, and 2.0%) and four levels of cationic rosin (0.5, 1.0, 1.5, and 2.0%) were considered to find the best alum/cationic rosin combination in acidic conditions (pH 5). After considering all aspects of the paper, such as the mechanical properties (tensile, burst, and tear indices), wet resistance (Cobb test and dynamic contact angle test), and chemical usage (economically and environmentally-friendly procedures), the 1.0% alum and 0.5% cationic rosin levels were selected for optimum performance. This research also showed that the combined effect of alum with cationic rosin was favorable. Moreover, the sequence of alum and cationic rosin addition, which is a challenge in paper mills, also should be considered. The results indicated that the addition of cationic rosin after alum obtained the best mechanical and wet resistance results. In addition, the results showed that both acidic and neutral pH were acceptable in this sizing process. [ABSTRACT FROM AUTHOR]