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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]

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]

• 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]

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]

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]

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]

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]

The surface application of starch is a well-established method for increasing paper strength. In surface sizing, a solution of degraded starch is applied to the paper. Two procedures have proved valuable for starch degradation in the paper mill: enzymatic and thermo-oxidative degradation. The objective of this study was to determine achievable efficiencies of cavitation in preparing degraded starch for surface application on paper. It was found that ultrasonic-assisted starch degradation can provide a starch solution that is suitable for surface sizing. The molecular composition of starch solutions prepared by ultrasonic treatment differed from that of starch solutions degraded by enzymes or by thermo-oxidation. Compared to commercial degradation processes, this resulted in intensified film formation and in greater penetration during surface sizing and ultimately in a higher starch content of the paper. Paper sized with ultrasonically treated starch solutions show the same strength properties compared to commercially sized paper. [ABSTRACT FROM AUTHOR]

This study investigated ink penetration through imaging technology, first by gray and contour mapping and then calculating the ink penetration depth by programing. Next, a series of further analyses were carried out, including average ink permeability, ink distributions, and printability of different uncoated inkjet paper with different parameters. The impact on ink penetration of the microstructure and hydrophilicity of the uncoated paper was also studied. The experimental results indicated that paper specimens with sizing agent were resistant to the ink, resulting in a slow and shallow ink penetration. Paper containing filler had a more hydrophilic surface and porous structure, leading to a faster and deeper ink penetration. However, the calendering operation could make the paper structure more compact and reduce the porosity and penetration depth. When an appropriate combination of sizing agent, filler content, and the calendering process was utilized, a more stable hue could be produced with improvements in optical density, saturation, and color. [ABSTRACT FROM AUTHOR]

Collagen extracted from leather waste was modified with maleic anhydride. Then, using ammonium persulfate as an initiator, by premodifying collagen reacted with styrene and ethyl acrylate monomers, a vinyl-grafted collagen sizing agent (VGCSA) for paper was prepared. Before the experiment, the performance of VGCSA was tested and VGCSA emulsion was applied to the surface sizing of the corrugated paper. Effects of the amount of VGCSA, the compound proportion of VGCSA, and starch and styrene-acrylic emulsion were studied relative to paper properties. The morphological changes of the paper before and after sizing were characterized by SEM. It was found that the collagen reacted with styrene and ethyl acrylate monomers. Through the grafting of vinyl and collagen, the crystallinity and thermal stability of VGCSA increased. The structure of VGCSA was spherical with a uniform size, and the average particle size was approximately 350 to 400 nm. After being sized, the surface fibers of paper became smooth and orderly. The optimal sizing of VGCSA was 8 g/m². The optimal proportion of VGCSA with starch was 4:6, and the optimal proportion of VGCSA with SAE was 2:8. The research indicates that collagen extracted from leather waste could be used as a biomaterial, and environmental and economic benefits could be created as well. [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]

The increase of paper size and production speed in wide-format inkjet printing systems is limited by significant in-plane deformation of the paper during printing. To increase both the production speed and paper size, the compensation of paper deformation is essential. A potential approach to compensate the paper deformation is actively changing the longitudinal paper position during a lateral pass of the printheads. This paper aims at developing an Iterative Learning Control (ILC) algorithm suited for this compensation strategy. The paper position is measured directly, but in non-real-time using image data obtained with a scanner located at the printheads. The proposed controller is experimentally validated and compared with standard norm-optimal ILC in a reproducible experiment, where a set of benchmark trajectories is used that represents severe paper deformation. The results show that in contrast to standard ILC, the ILC with basis functions achieves good tracking performance for the reference set and is hence a proper candidate algorithm for the compensation strategy. [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]

Precipitated calcium carbonate (PCC) is a filler that is widely used for papermaking, and lime sludge is a special type of PCC recovered from the black liquor from kraft pulping. There has been some concern that lime sludge may interfere with the development of paper's hydrophobicity in comparison with commercial PCC and ground calcium carbonate (GCC) due to the presence of impurities when alkyl ketene dimer (AKD) is used as the sizing additive. In this work, fillers with different particle size distributions were prepared, and the effects of particle composition on surface chemistry of fillers, adsorption for AKD, sizing degree of final paper sheets, and retention behavior of fillers were evaluated. The results showed that, through matching different particle size distributions for lime sludge fillers, the negative zeta potential decreased from -26.2 mV to -20.8 mV, the specific surface area decreased from 15.0 m²/g to 9.1 m²/g, and total pore volume decreased from 0.037 cm³/g to 0.026 cm³/g, which was favorable for the low adsorption for AKD. Consequently the sizing effect of filled paper was improved. Moreover, the retention rate also was increased by changing the particle size distribution of lime sludge. [ABSTRACT FROM AUTHOR]

In this work, a surface sizing agent for paper was prepared by the emulsion polymerization method, in which the collagen extracted from leather shavings was modified. The product was characterized using Fourier Transform-Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Energy Dispersive X-ray detector (EDX), and atomic absorption spectrophotometry. Corrugated papers were used as models. The synergy between modified collagen sizing emulsion and two commercial synthetic sizing agents was studied. Finally, the morphology of the papers before and after being treated was observed by Scanning Electron Microscopy (SEM). The results indicated that the sizing agent could be prepared using collagen as a raw material, which not only can alleviate a pollution problem in the leather industry, but also provide a novel alternative sizing agent for the paper industry, providing considerable economic, social, and environmental benefits to both industries. [ABSTRACT FROM AUTHOR]

Causticizing calcium carbonate (CCC), known as lime mud, is a byproduct of the papermaking industry that comes from the green liquor causticizing process. In China, CCC has been used as a paper filler to replace precipitated calcium carbonate (PCC). This is beneficial for saving resources and preventing secondary pollution. Unfortunately, compared with PCC, CCC can reduce the sizing efficiency of alkyl ketene dimer (AKD). So the application scope and dosage of CCC has been limited in mill trials in China. In this study, CCC was prepared with green liquor and quicklime, which were obtained from an alkali recovery line of a pulping mill. The reason for the lower sizing efficiency of AKD when CCC was used as a filler was investigated. The results showed that when greater amounts of AKD were adsorbed by CCC, the AKD sizing efficiency was lower. The irregular CCC had higher Brunauer, Emmett, and Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) method cumulative desorption pore volume, resulting in higher adsorption. The spindle-like or needle-like CCC had lower BET surface area and BJH method cumulative desorption pore volume that was beneficial for controlling its adsorption of AKD and improving the sizing efficiency. [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]

The sizing efficiency of maleated high oleic sunflower oil (MSOHO), a green reactive sizing agent, was studied in various sizing tests. MSOHO can be applied in the papermaking process according to protocols that are commonly used for the currently popular alkenyl succinic anhydride (ASA) sizing. While an adequate degree of sizing was reached with pure MSOHO, blends of MSOHO and fatty acid anhydride (FAA), another green sizing agent, gave even better results, coming close to the efficiency of pure ASA. Although both pure sizing agents - FAA as well as MSOHO - lack some efficiency when compared to ASA, blending those two sizing agents at an optimum ratio closes this gap with respect to ASA. This synergism was not caused by simply decreasing the viscosity of MSOHO. Blends of ASA-MSOHO and ASA-MSOHO-FAA were proposed for full-scale mill trials. [ABSTRACT FROM AUTHOR]

Maleated high oleic sunflower oil (maleated SOHO, MSOHO) is a promising substitute for alkenyl succinic anhydrides (ASA) that are widely used as sizing agents for paper. The part of the MSOHO molecule that is believed to be responsible for adhesion of the molecule onto cellulose, i.e., the maleated oleic acid moiety, was separately prepared and analytically characterized. Structural analysis was completed by studies of the molecular fragments obtained upon ozonolysis. The interesting question of whether there was a preferential reactivity during the ene-reaction of maleic anhydride with oleates was answered in a way that the newly formed double bond was placed to either side with no apparent selectivity. [ABSTRACT FROM AUTHOR]

Reactive paper sizing agents, such as alkenyl succinic anhydride (ASA), provide hydrophobicity to paper. The reactive anhydride group of these reagents is highly susceptible to reaction with water and thus resistance against hydrolysis is of primary importance for their practical application. This study describes different application-relevant properties of recently developed sizing agents that are based on renewable vegetable oils including hydrolysis behavior, time-dependent sizing efficiency, and tendency to form deposits or foam. The novel sizing agents - maleated high oleic sunflower oil (MSOHO) and maleated rapeseed oil (MRSO) - are compared to conventional ASA as the state-of-the-art sizing agent. Although the reactive group is the same in all reagents, there are pronounced differences between the three reagents, with MSOHO showing the best performance, i.e., the slowest hydrolysis. This oil has a higher ratio of hydrophobic side chains that impede the water attack at the anhydride group. Also, the higher viscosity of MSOHO plays an important role in performance, because diffusion of water molecules into a MSOHO emulsion droplet is much slower than in the case of conventional ASA. [ABSTRACT FROM AUTHOR]

Maleated oils derived from high oleic sunflower oil (MSOHO) have promising applications in paper sizing as a green alternative to conventional reactive sizing agents, such as alkenyl succinic anhydride. In this study, MSOHO was comprehensively characterized analytically by attenuated total reflection infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy with full resonance assignment, and mass spectrometry. [ABSTRACT FROM AUTHOR]

The hydrolytic stability and sizing behavior of a new paper sizing agent based on renewable vegetable oils (maleated sunflower oil, high oleic: MSOHO) was compared to two conventional alkenyl succinic anhydride (ASA) specimens, a commercial sample, and a reagent-grade ASA sample. At various pH conditions as well as upon addition of Ca2+ ions, MSOHO was more stable than both ASA samples. This superior stability of MSOHO was also supported by zeta potential measurements over 1 week. Whereas for sizing of paper higher dosages of MSOHO were needed to gain certain water repellency as compared to the ASA samples, the addition of alum had a pronounced positive effect on the sizing efficiency of MSOHO. The higher stability of MSOHO made it possible to size with an MSOHO-starch emulsion that was aged for one day at room temperature, when conventional ASA-starch emulsion had long lost any sizing efficiency. [ABSTRACT FROM AUTHOR]

Natural oils derived from linseed, rapeseed, soybean, and a special breed of sunflower were tested for the production of maleated fatty oils for paper sizing in the ene-reaction with maleic anhydride. All these maleated oils were subjected to a conventional sizing test proving their ability to hydrophobize handsheets. Natural oils having only monounsaturated fatty acid residues (oleic acid) in the triglycerides worked best by having lower product viscosity and higher yields. The optimized production procedure employs antioxidant addition, an increased maleic anhydride:triglyceride ratio of 4:1, as well as increased pressure to reduce undesired polymeric byproducts and to increase yield. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the development of a new experimental method suitable for the determination of the spreading velocity of surface active substances on a thin film of liquid substrate over a solid surface. Previous research showed that when oil and surfactants spread on the surface of a deep body of water, the spreading velocity is usually quite high, being in the range of several tens of centimeters per second. However, the spreading velocities of these substances on a thin water film are much slower. This is because that the spreading of an oil or a surfactant on water surface is not just a two dimension phenomenon, but a phenomenon involving the movement of water in a small depth below the surface. An additional process impeding oil or surfactant spreading in this situation is the interaction of the spreading molecules with the liquid/soild interface underneath water surface. The experimental method developed in this work uses a Wilhelmy balance to monitor the average spreading velocity of surface active substances on a thin water film over a porous solid substrate. The spreading of cellulose hydrophobization agents over wet paper web during the papermaking process is used as an example to demonstrate the capability of the method. [Copyright &y& Elsevier]

The effect of different surface sizing formulations on the chemical features of surfaces of the papers produced from Eucalyptus kraft pulp was studied. The surface analysis techniques, electron spectroscopy for chemical analysis and time-of-flight secondary ion mass spectrometry were applied. An uncoated base paper, the reference material, was sized with blends of cationic starch with either co-acrylonitrile-acrylate or co-styrene-acrylate. The results of both techniques are in good agreement and complete each other. It was possible not only to detect the presence of the surface sizing agents on the paper surface but also to distinguish them and evaluate their distribution and relative concentration. In addition, it was found that application of higher amounts of the sizing formulations, at a constant ratio of 20% copolymer to starch, did not significantly change the chemical properties of the paper surfaces. [ABSTRACT FROM AUTHOR]

Abstract: Mineral fillers have long been used in papermaking. The furnish of the writing and printing paper depends on using the fillers as internal or surface treatments. Talc, as an Egyptian filler material, was used as it is or after modification to be used as internal sizing for bleached rice straw pulp. Talc was modified chemically with phthalic anhydride and urea, as well as with using rosin size. Talc is chemically inert. The modification was carried out to change the nature of the native talc. The mechanical and optical properties for internal sizing papers were studied. The results indicated that modified talc with phthalic anhydride enhances the mechanical and optical properties for sized hand-sheets. It was clear that modification of the talc plays a role in improvement of the fiber–filler–fiber bond. [Copyright &y& Elsevier]

Commercial alkylketene dimer (AKD) waxes generally contain 80–90% AKD, and the rest of the components are by-products such as fatty acids, fatty acid anhydrides, and AKD oligomers. In this article, the effects of fatty acid components present in AKD waxes on AKD emulsion stability and paper sizing performance were studied using AKD emulsions, which were prepared from an AKD wax mixed with 0–12% stearic and palmitic acids. Repeated temperature shock treatments revealed that the fatty acids–containing AKD emulsions became most unstable at 3% fatty acid content, whereas those with 12% fatty acids were rather stable. When the addition level of fatty acids was increased up to 12%, zeta potentials of the AKD emulsion particles increased from +1.4 mV to +4.4 mV with increasing fatty acid content. This increase in zeta potential may be one of the factors that lead to a decrease in AKD retention ratios in handsheets. Thus, fatty acid components present in AKD waxes not only decrease the pure AKD content in the waxes but also have negative impacts on emulsion stability and paper sizing performance. These results show that fatty acid content in AKD waxes must be sufficiently controlled as low as possible to keep a standard level of the AKD wax quality. [ABSTRACT FROM AUTHOR]

Compared with conventional acidic rosin emulsion size, neutral rosin size has good sizing efficiency under neutral–alkaline conditions of paper manufacture because its emulsion particles are stable to the action of hydroxide ions. Therefore, the sizing efficiency of emulsion-type rosin sizes, i.e. their ability to increase resistance to fluid penetration, was considered to be related with their particulate structure. The supramolecular structure of the neutral glycerin rosin ester–rosin size microparticles and acidic rosin size microparticles were investigated by using differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) absorption spectroscopy, and electron spectroscopy for chemical analysis (ESCA) techniques in this study. The results indicated that the neutral glycerin rosin ester–rosin size is quite distinct from the acidic rosin sizes in their particulate supramolecular structure. A glycerol dirosinate bilayer existed in the particle structure is hypothesized for the neutral glycerin rosin ester–rosin size microparticles. The results also suggest that the glycerol dirosinate bilayer distributes on the outermost layer of the neutral rosin size microparticles, covering the rosin acid molecules, so as to prevent the dissociation of rosin by hydroxide ions under neutral–alkaline conditions. Consequently, the difference in the supramolecular structure of the rosin sizes particles resulted in their different stabilities and retention characteristics. [Copyright &y& Elsevier]

Utilizing the assembly and formation of laponite/lauric arginate (LAE) complexes near the water-oil interface, where laponite and LAE interact, the stability and preparation of alkyl ketene dimer (AKD) Pickering emulsions with tunable shells were investigated. Stable spherical emulsions were generated with homogenization due to the interfacial jamming of laponite/LAE complexes. The packing density of laponite at the oil/water interface was adjustable via LAE concentration tuning. The Pickering system with a tunable shell, droplet size, resistance to oil agglomeration and hydrolysis over a long period of time was achieved based on LAE loading. Hydrophobic paper with a 126.6° of water contact angle was prepared under a surface sizing process with the laponite/LAE-stabilized AKD emulsion loading of 0.12 wt% LAE, which exhibited 90 days' long-term storage stability. The confocal laser scanning microscopy (CLSM) shows that laponite/LAE forms a dense layer at the oil/water interface and 3D-network in a continuous phase. The properties provided by laponite/LAE, a highly efficient complex with resistance to phase permeability and hydrolysis, open new opportunities in biodegradable and food-grade emulsifiers for paper sizing agents, where LAE achieves synergistic effects with laponite. [Display omitted] • LAE adsorption to laponite notably impacted the properties of laponite. • Using LAE to adsorb to laponite is an environmentally friendly surface modification technique. • pH plays a significant role in AKD emulsion loading of laponite/LAE complexes. • Tunable shells were controllably achieved based on LAE loading. • Long-term storage and sizing performance of AKD can be changed based on LAE loading. [ABSTRACT FROM AUTHOR]

Part 4. Focuses on the chemistry involved in the sizing of acid and alkaline papers. Types of fillers used; Advantages and disadvantages of alkaline papermaking; Source of acidity in paper; Description of deacidification methods; Enhancement of long-term stability of papers; Reasons for the increase in demand for alkaline papermaking.

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. Unlabelled Image • CNQD adsorption improved the Laponite hydrophobic property and the adsorption efficacy at the ASA-water interfaces. • The Pickering emulsion's stabilization mechanism was adequately illustrated using Laponite/CNQDs as fluorescent probes. • Different concentrations of Laponite do not induce CNQD fluorescence quenching. • Laponite/CNQDs can maintain ASA emulsion stability over extended aging periods and sustain high sizing performance [ABSTRACT FROM AUTHOR]

Internal sizing agents make it possible to prepare water-resistant paper from an aqueous suspension comprising water-loving fibers and an emulsified hydrophobic agent. Why doesn't the hydrophobic treatment get in the way of inter-fiber bonding? The answer appears to involve the order in which nano-scale events happen during the manufacture of paper. It appears that the inter-fiber bonded areas develop first. Molecular distribution of the hydrophobic agents appears to happen later, especially during the later stages of evaporative drying. The topic seems to be crying out for someone to carry out appropriate experiments to shed more light on the mechanism. [ABSTRACT FROM AUTHOR]

The maleopimaric acid is the main component of modified colophony rosin. The main use of maleic-modified rosins is in paper size, while its esters are mainly used in printing inks. The article examines the sensitizing capacity of maleopimaric acid. The compound was synthesized and its structure was determined. Maleleopimaric acid was found to be very potent sensitizer comparable with the strongest allergen isolated from unmodified colophony of the gum rosin type. It is concluded that the modification of colophony might form new potent allergens not found in unmodified colophony.