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Mineral fertilizers and water are essential for food production, and their sustained delivery is imperative to maximize crop yields. During heavy rainfalls, fertilizers can leach into the environment. During drought, fertilizers cannot dissolve in the soil. Superabsorbent polymers (SAP) can improve soil water retention capacity, by absorbing water during rainfall and releasing it during dry periods. In this study, we have integrated varying levels of calcium nitrate and zinc sulfate in an SAP to achieve fertilizer-SAP composites. Fertilizer-SAP composites can both help alleviate fertilizer leaching during heavy rainfall and facilitate their dissolution during dry periods, thank to moisture they absorb from the soil. SAP composites can also slow down the release of nutrients and keep them closer to the root area, for optimum plant uptake. Furthermore, we have observed a synergistic effect of nutrient incorporation in SAP, manifested by the enhanced water uptake of composites compared to pure SAP. For instance, SAP composites with 17 wt% zinc sulfate and calcium nitrate achieved superior water absorptions of 1462 and 1626 g/g, respectively. In comparison, pure SAP in this study reached approximately 800 g/g, and most commercial SAPs have water absorption capacities of 500 g/g. Suggested SAP application is often reported as 15–45 kg per hectare, in the literature. In comparison, the recommended zinc and calcium doses are as low as 3–5 kg/ha. Therefore, by a single fertilizer-SAP application, farmers can cover both the SAP and zinc, or calcium demands of their fields. [ABSTRACT FROM AUTHOR]

This study focuses on enhancing cementitious materials by incorporating silanized graphene oxide (SGO) and superabsorbent polymers (SAPs), aiming to improve their mechanical and durability properties. The primary goal is to evaluate the effects of SGO/SAP composites on the hydration, absorption, shrinkage, and overall performance of concrete. The composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) to understand their microstructure. Mechanical and durability tests revealed that adding SGO/SAP composites significantly increased the mechanical strength and water absorption capabilities of the concrete. The compressive strength, split tensile strength, and flexural strength of the SGO/SAP-modified concrete were measured at 57 MPa, 4.90 MPa, and 8.25 MPa, respectively. Shrinkage tests demonstrated the composite hydrogel's excellent water-holding capacity at 0.3 wt.% SGO/SAP, facilitating internal curing in concrete structures. FE-SEM analysis indicated a reduction in microcracks due to the presence of SGO/SAP. The improvements are attributed to the synergistic effects of SGO and SAP, which enhance water retention, dispersion, and interfacial bonding within the cementitious matrix. The microstructural studies confirmed the exceptional stability of the SGO/SAP-modified mix, emphasizing its potential as an additive to improve concrete properties. This research underscores the significant potential of SGO and SAP in advancing the performance of cement-based materials, highlighting their applicability in infrastructure development and construction for creating more durable and high-performing concrete structures. HIGHLIGHTS: The SGO/SAP significantly enhances the durability of cement-based materials. The SGO/SAPs exhibit superior water absorption and retention properties. Enhanced mechanical strength of SGO/SAP hydrogel-modified concrete. The durability characteristics of cement mortar improved by SGO/SAP hydrogel A decrease in the agglomeration of nanocomposite particles [ABSTRACT FROM AUTHOR]

High-strength concrete is more sensitive to changes in curing conditions and has a higher tendency to crack. To mitigate shrinkage and sensitivity to curing conditions, various methods, such as internal curing (IC) agents, have been proposed. Various types of materials, including pumice, ceramic aggregates, recycled concrete aggregates, perlite, and superabsorbent polymers (SAP), have been used for internal curing. Due to the difference in absorption content and rate of water absorption and desorption between SAP and recycled lightweight aggregate, their effect on the properties of high strength concrete can be different. This study explores the impact of IC using SAP on compressive strength, plastic shrinkage, and restrained shrinkage from drying in HSC, comparing it with IC using recycled lightweight aggregate (LWA).The utilization of pre-soaked SAP as an IC agent resulted in a minor enhancement in the workability of concrete. The use of LAW has reduced the workability of concrete. Because the shape of LAW particles is crushed, unlike SAP spherical particles. The results showed that pre-saturation with a superabsorbent polymer or recycled LWA slightly boosts compressive strength under drying conditions. The compressive strength of compounds with SAP and LAW in drying conditions was lower than that of the control mixture in standard curing conditions. This suggests that despite the favorable impact of IC with SAP and LAW on compressive strength, it does not fully address the decrease in concrete strength resulting from unfavorable curing. Regarding the effect of IC on shrinkage cracks, while IC with a recycled LWA proves more effective in reducing restrained shrinkage, IC with a superabsorbent polymer is more efficient in mitigating plastic shrinkage and minimizing concrete cracking risks. [ABSTRACT FROM AUTHOR]

The iron implemented in superabsorbent hydrogel (SAH). SAP (superabsorbent polymer) was modified by intermixing with iron microelement in itaconic acid and carboxymethylated tamarind kernel gum. Different samples were prepared for various compositions of SAH by changing the concentration of monomer, initiator, and cross-linker. Iron chloride was interpenetrated in the best-swelled hydrogels for releasing of iron as micronutrient. The characterization of synthesized hydrogel and modified FSAH was done by FTIR, SEM, and TGA analysis. Different behaviors of synthesized hydrogels in terms of weather conditions and pH (3, 8, and 10) of soil were studied. The swelling degree was studied by kinetic modeling of iron release by using the Higuchi model and the Korsmeyer–Peppas model which represent that high number of regression coefficients (R2) more equal to unity, fitted well in the iron release pattern in water and soil. On the other hand, diffusion quotient (n) showed in the Fickian diffusion model applied for the procedure of iron release. The iron superabsorbent hydrogel (FSAH) was used for the study of marigold plants germination and growth. It was also found that the germinated population with FSAH is much higher as compared to those without modified SAH. [ABSTRACT FROM AUTHOR]

This study investigates the synergistic effects of SAP and fly ash on the mechanical properties and microstructure of mortar. The impact of varying SAP particle sizes and contents on fluidity, compressive strength, flexural strength, and porosity in fly ash cement-based materials is analyzed. The MIP method analyzes the mercury intrusion and extrusion curves, along with fractal dimensions, while SEM is employed for matrix observation. Results indicate that adding SAP reduces mortar fluidity, which further declines with increasing SAP particle size and content. The addition of SAP has a dual effect on the mechanical properties of mortar. Large SAP particle sizes and high content significantly increase porosity, leading to a reduction in compressive strength. Furthermore, SAP enhances the roughness of the mortar surface, lowers the overall fractal dimension, and simplifies the pore structure. As particle size and content rise, both compressive and flexural strengths decrease, with total porosity increasing consistently. [ABSTRACT FROM AUTHOR]

Engineering materials such as geosynthetics clay liners (GCL) and gravel layers are effective to cut off the in-soil water migration and have been widely employed to stabilize the moisture content of subgrades. However, the moisture stabilizing performance of GCL or gravel layer is usually compromised due to the complexity of service condition. This paper introduces an engineering material named restraining moisture geotextiles (RMG), which is expected to show low permeability as GCL. With characterization of basic properties of RMG, moisture migration column test of silty soil and test cases with employments of RMG, GCL, and gravel layer are performed, respectively. The temperature and moisture fields of soil columns subjected to a freezing-thawing process are measured, and the capillarity and in-soil water migrating behavior are analyzed. Carbon footprints of GCL and RMG are compared and discussed. Test results show that RMG, GCL and gravel layer are effective to cut off the capillarity, but the gravel layer can result in higher moisture content in silty soil due to the vapor migration and capillary isolation. In conclusion, RMG can be an alternative method with low permeability on reducing the in-soil water migration, and is much lighter and more engery-efficient than GCL. • Restraining moisture geotextile saves more energy than geosynthetics clay liner. • Restraining moisture geotextile can stabilize moisture field in soil effectively. • Gravel layer results high moisture in silt with limited control of vapor migration. • Absorbency of restraining moisture geotextile is sensitive to loading pressure. [ABSTRACT FROM AUTHOR]

To explore the long-term crack resistance of pavement concrete containing superabsorbent polymer (SAP), a fatigue test was designed with the consideration of rolling fatigue load and temperature coupling. The four-point fracture and acoustic emission tests were combined to evaluate the evolution of crack resistance. Additionally, the enhancement mechanism was revealed through scanning electron microscopy and mercury intrusion porosimetry experiments. The results indicate that the coupling effects of rolling fatigue load and temperature accelerate the deterioration of the fracture performance of concrete, particularly the freeze–thaw conditions. The concrete with SAP had greater fracture toughness, with improvements of 9.3%, 11.9%, and 58.1% under the coupling rolling fatigue loading and high temperatures, low temperatures, and freeze‒thaw cycles, respectively. The fracture process of concrete with SAP includes fluctuation, fatigue accumulation, and fatigue failure periods, and the SAP delays the arrival time of cumulative ring count and energy, significantly reducing the rate of concrete damage. More fibrous C-S-H and ettringite were generated at the interface microcracks in the concrete containing SAP, confirming the greater degree of hydration. Moreover, the SAP reduced the porosity and average pore size, which enabled the concrete to better resist the impact of rolling fatigue loading and adverse environmental temperatures. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the use of a superabsorbent polymer (SAP) to provide improvements in the handling properties of iron ore tailings (IOT). The material studied came from the magnetic separation reprocessing of the material discarded at the Gelado Dam, located in Serra dos Carajás in the state of Pará, Brazil. While the concentrate presents reasonable handling conditions, the tailings, with 61.5% iron, 15% moisture, and 39% of the mass, have high cohesiveness and adhesiveness due to their fine nature and the climatic conditions of the Amazon rainforest. However, the tailings can still be considered a product as long as the handling and transportation logistics are feasible. Thus, studies with an SAP and IOT were carried out in a bench rotating drum to promote mixing between them, and the main variables studied were the SAP dosage and the required contact time. The improvement in the physical properties of the IOT were evaluated considering the Hausner ratio, Carr index, Jenike's flow function index, Atterberg limits, and chute angle. The superabsorbent polymer promoted a significant improvement in the state of consistency of the material, and the best performance was obtained with a dosage of 1000 g t−1. As long as a suitable contact condition was promoted, a contact time of 1 min was enough to achieve the expected benefits. After dosing with the superabsorbent polymer, the material's handling classification changed from 'cohesive' to 'easy flow', and the chute angle was reduced from 90° to levels below 60°. It was concluded that the application of the superabsorbent polymer has the potential to improve the fluidity of the material discarded in the magnetic concentration operation, allowing it to be handled throughout the production and transportation chain. The SAP appears to be an important additive for the full use of the material present in the dam (100% recovery), with both economic and socio-environmental benefits. [ABSTRACT FROM AUTHOR]

To achieve the organic combination of rainwater resource recycling and urban construction, this study innovatively prepares a dry cement-based water absorbing material (DCWAM) using superabsorbent polymers (SAP) and expanded perlite (EP). A systematic study based on response surface methodology focuses on mechanical properties, water absorption properties, and deformation properties to achieve optimization of DCWAM mix proportions. Moreover, the influence of SAP and EP on the microstructure characteristics of DCWAM is revealed through SEM and XRD analysis. Experimental results show that with the addition of SAP and EP, the flexural strength initially increases and then decreases, while the compressive strength shows a decreasing trend. After water absorption, the above properties decrease by 50.67% and 46.03%, respectively, resulting from the accelerated internal crack development caused by the water absorption expansion of SAP and EP. The addition of EP increases the water absorption rate of DCWAM, slows down the development of cracks under external forces, and improves deformation performance. For SAP, the early water absorption rate is reduced, but it can achieve more sustainable water absorption, thereby improving the final water absorption rate. When 0.3% SAP and 17.5% EP are added, the water absorption rate reaches its maximum, which is 38.4% of its own weight, about 20 times that of ordinary cement paste. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the use of a superabsorbent polymer (SAP) to provide improvements in the handling properties of iron ore tailings (IOT). The material studied came from the magnetic separation reprocessing of the material discarded at the Gelado Dam, located in Serra dos Carajás in the state of Pará, Brazil. While the concentrate presents reasonable handling conditions, the tailings, with 61.5% iron, 15% moisture, and 39% of the mass, have high cohesiveness and adhesiveness due to their fine nature and the climatic conditions of the Amazon rainforest. However, the tailings can still be considered a product as long as the handling and transportation logistics are feasible. Thus, studies with an SAP and IOT were carried out in a bench rotating drum to promote mixing between them, and the main variables studied were the SAP dosage and the required contact time. The improvement in the physical properties of the IOT were evaluated considering the Hausner ratio, Carr index, Jenike’s flow function index, Atterberg limits, and chute angle. The superabsorbent polymer promoted a significant improvement in the state of consistency of the material, and the best performance was obtained with a dosage of 1000 g t−1. As long as a suitable contact condition was promoted, a contact time of 1 min was enough to achieve the expected benefits. After dosing with the superabsorbent polymer, the material’s handling classification changed from ‘cohesive’ to ‘easy flow’, and the chute angle was reduced from 90° to levels below 60°. It was concluded that the application of the superabsorbent polymer has the potential to improve the fluidity of the material discarded in the magnetic concentration operation, allowing it to be handled throughout the production and transportation chain. The SAP appears to be an important additive for the full use of the material present in the dam (100% recovery), with both economic and socio-environmental benefits.

Abstract This study shows the impact of varying cement content while maintaining a constant water-to-cement (w/c) ratio on the performance of self-healing concrete. It also explores the effect of F-type fly ash on the self-healing mechanism of concrete. Self-healing concrete, incorporating super absorbent polymers, offers a viable remedy to diminish the detrimental effects of cracks, enhancing the durability and lifespan of concrete structures. While the w/c ratio is a crucial factor influencing concrete properties, the impact of varying cement content under a constant w/c ratio in self-healing concrete remains understudied. Therefore, this experiment involved preparing 18 different concrete mixtures using three distinct cement contents under three specific w/c ratios. Fly ash was mixed in half of the specimens. Super absorbent polymers are incorporated into all mixtures to facilitate autonomous healing by absorbing and retaining water, which is released upon crack formation. Specimens were pre-cacked using a stress-controlled UTM machine. To evaluate the self-healing mechanism, low water pressure permeability test, water absorption test, and image analysis were conducted at 7, 14, 28, and 56 days. The findings of this study show that a w/c ratio of 0.35 yielded the best performance which indicates a lower w/c shows a higher self-healing performance. Additionally, the specimen containing a higher cement content exhibited enhanced healing capacity compared to other specimens. However, the specimens with fly ash failed to show a satisfactory result on self-healing capacity because the addition of silicon-based fly ash (F type) created an adverse effect on the self-healing mechanism.

The aim of this paper is to review the developments in the use of superabsorbent polymer (SAP) in cementitious materials. This review covers the classification, properties, and methods for testing SAP, along with its impact on concrete properties, and other noteworthy developments in SAP usage. Various methods can be used to test the water absorption by SAP. Among them, the tea bag method is considered a simple and time-saving test, while centrifuge and suction filtration methods are regarded as accurate because they remove inter-particle liquid. The water absorption by SAP is affected by factors such as SAP composition, method of preparation, physical characteristics, and properties of the fluid. Higher fluid temperature (e.g., 60 °C) leads to greater absorption and release distance, while higher pH levels (pH 13) result in lesser absorption. The optimal dosage of SAP varies between studies, generally ranging from 0.1% to 1.5%. Higher SAP content (0.3–8%) reduces workability and decreases slump. Results related to strength vary; some studies have reported increased strength due to SAP's maintenance of higher internal relative humidity, while others have observed decreased strength due to increased porosity caused by SAP. The inclusion of SAP typically leads to a strength recovery of about 10% over time due to the continuous hydration process. Curing methods also influence strength, with sealed curing showing greater strength. Additionally, an increase in SAP dosage (0.1–0.6%) reduces shrinkage. Furthermore, the paper discusses the challenges encountered while using and testing SAP, as well as the explanations provided by researchers. [ABSTRACT FROM AUTHOR]

This study aims to synthesize and characterize a sulfated‐starch‐based superabsorbent polymer (S‐SAP). The S‐SAP is prepared by grafting 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) and acrylic acid (AA) onto sulfated starch, which is subsequently crosslinked using N,N‐methylene‐bis‐acrylamide (MBA) via free radical polymerization with ammonium persulfate as the initiator. The successful grafting of AA and AMPS onto the starch backbone improves the thermal stability and increases the swelling capacity of the polymer. The swelling capacity and reusability of the S‐SAP are compared with those of commercial superabsorbent polymers (C‐SAPs). The swelling capacity of the S‐SAP is higher than those of C‐SAPs, reaching 417 g g−1 in distilled water and 47 g g−1 in a 0.15 M NaCl solution. The water absorption kinetics of the S‐SAP shows a good fit with the pseudo‐second‐order model. The polymer prepared herein has potential applications in horticulture and agriculture. [ABSTRACT FROM AUTHOR]

Superabsorbent polymers (SAPs) are effective soil amendments that can control soil erosion by improving soil quality. However, many commercial SAPs face challenges including limited biodegradability, high costs, and adverse effects on soil hydrological properties, which can lead to increased water and soil loss. This study examined the potential of lower dosages of biodegradable SAPs to improve the hydrological properties of "Shimajiri-maji" (clay) soil. Three concentrations of biodegradable Fasal Amrit polymer (EFP) (P1: 0, P2: 3 g m−2, and P3: 6 g m−2) were evaluated under three simulated rainfall intensities (I1: 35; I2: 70 and I3: 110 mm h−1) and two gradients (7.5%, and 15%) during consecutive storms. The time to generate runoff, infiltration, runoff, soil loss, and water storage (WS) were quantified over one hour. The results show that runoff generation was delayed in EFP-treated soils compared to the control. Both polymer treatments enhanced infiltration (P2 > P3 > P1) and reduced runoff and soil loss (P2 < P3 < P1). Higher EFP rates improved water storage at surface depths (P3 > P2 > P1). EFP-treated soils exhibited lower interrill erodibility, suggesting greater resistance to soil erosion compared to the control. EFP treatments also significantly improved the soil's physical properties (bulk density, porosity, organic matter, aggregate stability). EFPs can diminish runoff and soil loss as the EFP-treated plots exhibited greater aggregate stability than the control. It was concluded that low EFP concentrations can improve soil hydrological properties and mitigate soil erosion. Further investigations are needed to optimize the EFP concentrations for different soil types. [ABSTRACT FROM AUTHOR]

BACKGROUND: Acrylamide‐based bait has super water absorption making it highly attractive to subterranean termites that are lured by wood with high water content. This study investigated the control efficiency of these baits on subterranean termites. In particular, we evaluated the water‐absorption capacity, attractiveness to subterranean termites, and control efficiency of these baits on subterranean termites through wooden blocks (Populus deltoides and three types of particleboards). RESULTS: The results indicated a substantial water absorption capacity of acrylamide (70.6%; control: 14.8%) and a strong attraction for feeding subterranean termites (P. deltoides: 198 highest; 81 lowest subterranean termites individuals; combination of neem leaves and walnut shells: 168 highest; 36 lowest subterranean termites individuals). When acrylamide was combined with boric acid at the highest concentration, it resulted in the lowest wood consumption rates (P. deltoides: 24.1%; control: 63.8%, combination of neem leaves and walnut shells: 32.5%; control: 62.1%). CONCLUSIONS: In conclusion, this research supports the commercial viability of employing innovative acrylamide‐based toxic baits and particleboards for subterranean termite management. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study investigated the mechanical responses and self-healing capability of incorporating superabsorbent polymer (SAP) particles in Fibre-Reinforced Ultra-High-Performance Concrete (UHPC) mixes under repetitive flexural and sustained tensile loadings. UHPC with SAP addition of 0.3% and 0.4% of the binder ratio were studied along with a control UHPC mix. The methodology included investigating the mechanical properties of these mixes under ambient, water, and 100% of relative humidity (RH) curing conditions. In addition, the mechanical performance of ambient-, water-, and 100% RH-cured prismatic specimens (100 mm × 100 mm × 500 mm) under repeated load was studied under the same curing conditions. Prismatic specimens (75 mm × 75 mm × 500 mm) were kept under cure conditions of wet and dry cycles with applied tensile load for 28 days for the sustained tensile load. The results showed that incorporating SAP into UHPC enhances the elastic modulus, flexural strength, and tensile strength. Also, mixes with SAP have exhibited compressive strength above 120 MPa after 90 days. Furthermore, the load recovery of the prisms under repetitive flexural load and prisms under sustained tensile loading demonstrated the self-healing efficiency of SAP incorporated into the UHPC mixes higher than the control mix specimens. [ABSTRACT FROM AUTHOR]

In this study, biocompatible and biodegradable superabsorbent polymers (SAPs) were prepared from carboxymethyl cellulose (CMC) using citric acid as a crosslinking agent, utilizing a high-concentration CMC paste and a short annealing process. The effects of CMC molecular weight, annealing temperature and time, and crosslinker concentration on the absorption properties in saline solution were evaluated. In addition, the effects of mixing CMC SAPs with different molecular weights were explored to optimize performance. The results showed that CMC molecular weight significantly affected absorption properties, with medium molecular weight (395 kDa) exhibiting the best overall performance. The content of the crosslinking agent and annealing conditions were also critical—higher crosslinking improved absorption under load but reduced free swell absorption and retention. In addition, the absorption properties could be optimized by appropriately mixing the CMC SAPs with different molecular weights, indicating complementary interactions that enhance performance beyond the individual contributions of each SAPs. These findings can contribute to the development of environmentally friendly, high-performance superabsorbent materials for personal care products as a sustainable alternative to conventional petroleum-derived SAPs. [ABSTRACT FROM AUTHOR]

Over the past two decades, the development and commercialization of slow-release fertilizers (SRFs) have significantly advanced, with the primary aim of mitigating environmental issues associated with excessive fertilizer use. A range of methodologies, including chemical and physical reactions, incorporation into carriers with porous and layered structures, and coating techniques, have been explored and refined. On the other hand, global challenges such as drought and desertification further underscore the need for SRFs that not only control nutrient release but also improve soil moisture retention. This paper reviews the development and application of eco-friendly starch hydrogels as fertilizer carriers and water retention for SRFs, particularly starch-based superabsorbent polymers (SAPs) produced through grafting copolymerization with acrylamide. This review explores both scientific issues, such as the microstructures and releasing mechanisms of SAPs, and technical development, involving copolymerization technologies, multi-initialization processes, methods of loading fertilizer into hydrogel, etc. Starch, as both a biodegradable and renewable carbohydrate polymer, offers distinct advantages due to its excellent chemical stability and high reactivity. The fabrication techniques of SAPs have been developed from traditional batch polymerization in aqueous solutions to more efficient, solvent-free reactive extrusion. The benefits of SRFs based on SAPs encompass enhanced soil aeration, the prevention of soil deterioration, the minimization of water evaporation, environmental pollution control, reduction in plant mortality, and prolonged nutrient retention within soil. In this review, we summarize the current progress, identify limitations in existing technologies, and propose future research directions to further enhance the performance of starch-based SRFs. [ABSTRACT FROM AUTHOR]

Treated tritium-containing water is stored in tanks at the Fukushima Daiichi Nuclear Power Plant until ocean discharge is completed; however, the risk of leakage and contamination remains. We propose the combination of a superabsorbent polymer and an anion-supporting hydrogel for the safe and long-term storage of this water. The external radiation resistance of these materials in the presence of water was investigated, and their water absorption and Cs+ and I retention capacities following irradiation to a cumulative absorbed dose of up to 40 Gy were determined. The superabsorbent polymer demonstrated good water retention and Cs+ adsorption capability. The saturated I adsorption capacity of the hydrogel was 575 ± 28 mg/g, and maintained up to an absorbed dose of 100 Gy. The proposed method can be implemented until the planned completion of water processing even if the storage location has a dose rate of 100 µGy/h. [ABSTRACT FROM AUTHOR]

Copyright of China Fiber Inspection / Zhongguo Xian-Jian is the property of China Fiber Inspection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Superabsorbent polymers (SAPs) have a remarkable ability to absorb significant quantities of water. However, their absorption capacity is significantly reduced when exposed to saline solutions, such as urine, due to the polyelectrolyte effect and charge screening. Methods: In this study, we demonstrate a zwitterionic superabsorbent polymer (ZSAP) with excellent salt-water absorption and retention capacities. ZSAP was synthesized by grafting a copolymer of p(sulfobetaine methacrylate-co-2-hydroxyethyl methacrylate) (p(SBMA-co-HEMA)) onto an acrylic acid (AA)-based hydrogel via free-radical polymerization. The introduction of zwitterionic SBMA significantly enhances the hydrophilicity of the polymer, particularly in a saline solution due to the anti-polyelectrolyte effect, thereby accelerating the rate of salt absorption. Additionally, the hydroxyl groups from HEMA facilitate the formation of covalent bonds with the AA network membrane through esterification, effectively mitigating polymer leaching. The hydration/dehydration behaviors of linear polymers were measured using the dynamic vapor sorption (DVS) method. Moreover, the salt-water absorption capacity, centrifuge retention capacity (CRC), and absorbency under load (AUL) of ZSAP with various SBMA moieties and copolymer dosages were comprehensively evaluated in a 0.9 wt% sodium chloride solution. Additionally, the water retention under different temperatures and polymer leaching of ZSAP were investigated. Significant Findings: The copolymer p(SBMA-co-HEMA) not only demonstrates a high salt-water absorption rate at 90% RH in a 0.9 wt% NaCl solution but also exhibits superior water retention at 0% RH compared to the AA polymer. Moreover, the ZSAP exhibits superior salt-water absorption capacity and AUL in a 0.9 wt% NaCl solution compared to conventional AA-based SAP. Additionally, the introduction of the hydroxyl moiety from the p(SBMA-co-HEMA) copolymer reduces free polymer leaching from ZSAP. This work presents an approach for the development of new SAP with high salt-water absorption and retention.

This study investigated the effects of a crystalline admixture (CA) and superabsorbent polymer (SAP) on the self-healing and mechanical properties of basalt fibre mortars. Uniaxial compression experiments were conducted on basalt fibre mortar specimens to investigate the effects of the two admixtures and different admixture ratios on the strength repair ability of basalt fibre mortar at different maintenance ages after pre-cracking, and microscopic observations of cracks and their healing products were conducted using optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy to verify the experimental results. The results showed that CA has a noticeable advantage in the self-healing of microcracks by producing a dense material through chemical reactions, whereas SAP can effectively fill wider cracks and reduce their width through physical expansion. Compared with CA, SAP had a greater effect on the compressive strength of the basalt fibre mortars. The simultaneous dosing of CA and SAP in appropriate amounts can effectively combine the advantages of CA and SAP to optimise the self-healing effect of basalt fibre mortars, generating self-healing fillers based on calcium silicate and calcium carbonate in the cracks and enhancing the repair strength of basalt fibre mortars with a self-healing rate of 103%.

This study aimed to experimentally investigate the compressive strength and air voids of cement pastes with varying dosages of Superabsorbent Polymer (SAP) and water-to-cement (w/c) ratios. Cement pastes were prepared using three different w/c ratios of 0.4, 0.5, and 0.6, along with different dosages of SAP ranging from 0.2% to 0.5% by weight of cement. Additionally, SAP was introduced in two forms: dry and wet. After casting the cubes, two distinct curing conditions were employed: curing at a temperature of 20 °C with a Relative Humidity (RH) of 60% (Curing 1), and water curing (Curing 2). The results revealed that the addition of SAP increased early strength when subjected to Curing 1, followed by a decrease in later strength. On the other hand, samples with SAP and water curing exhibited higher strength compared to those without SAP, especially with w/c ratios of 0.4 and 0.5. However, at a w/c ratio of 0.6, nearly all samples showed a reduction in strength compared to those without SAP. Furthermore, air void analysis was performed on all samples cured for 28 days using an image analysis technique. The samples containing wet SAP resulted in a higher total air content compared to the samples with dry SAP. Additionally, the incorporation of wet SAP in cement paste led to lower specific surface areas and a higher spacing factor than the samples with dry SAP. These findings suggest that the clumping of wet SAP particles during presoaking resulted in coarser air voids compared to the samples containing dry SAP. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The adsorption mechanism of superabsorbent polymer (SAP) can provide theoretical guidance for their practical applications in different environments. However, there has been limited research on the mechanism of attapulgite–sodium polyacrylate. This research aimed to compare the Cd(II) adsorption characteristics and water retention properties of organic–inorganic composite SAP (attapulgite–sodium polyacrylate, OSAP) and organic SAP (polyacrylamide, JSAP). Batch experiments were used to investigate the kinetics of Cd(II) adsorption, as well as the thermodynamic properties and factors influencing these properties. The results show that the Cd(II) adsorption capacity was directly proportional to the pH value. The maximum adsorption capacities of OSAP and JSAP were of 770 and 345 mg·g−1. The Cd(II) adsorption for OSAP and JSAP conformed to the Langmuir and the quasi-second-order kinetic model. This indicates that chemical adsorption is the primary mechanism. The adsorption process was endothermic (ΔH0 > 0) and spontaneous (ΔG0 < 0). The water adsorption ratios of OSAP and SAP were 474.8 and 152.6 in pure water. The ratio decreases with the increase in Cd(II) concentration. OSAP and JSAP retained 67.23% and 38.37% of the initial water adsorption after six iterations of water adsorption. Hence, OSAP is more suitable than JSAP for agricultural and environmental ecological restoration in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Cracking and repair of concrete have always been the focus of attention in engineering field. Superabsorbent polymers (SAP) have a certain crack self-healing function. In this paper, the liquid absorption properties of SAP under different environmental solutions (NaOH, NaCl and distilled water) were tested. The compressive strength recovery rate of cracked specimens, the self-healing rate of different crack widths (0.1, 0.2 mm) and the crack filling state were used as repair indicators. The repair effect of SAP with different mass fractions (0%, 0.5%, 1.0%) on cracked mortar specimens under different environmental solutions was analyzed. The results show that the liquid absorption rate of SAP in different environmental solutions increases rapidly and then tends to be stable, and the liquid absorption rate of SAP in NaOH environmental solution is the highest. The incorporation of SAP improves the compressive strength recovery rate of cracked mortar specimens under different environmental solutions to a certain extent. Among them, the compressive strength recovery rate of specimens mixed with 0.5% SAP in NaOH environmental solution for 28 d is the highest, which is 17% higher than that of reference group. The incorporation of SAP improves the self-healing properties of mortar specimens with different crack widths in different environmental solutions. With the increase of SAP content, the self-healing properties of mortar specimens with 0.2 mm crack width repaired in NaOH environmental solution for 28 d is significantly higher than that of distilled water and NaCl solution. The self-healing rate of specimens with 1.0% SAP in NaOH environmental is 90%. The incorporation of SAP cooperates with hydration products to seal the crack mouth, so it is beneficial to solution improve the durability of cement mortar. [ABSTRACT FROM AUTHOR]

Cement-based materials are fundamental in the construction industry, and enhancing their properties is an ongoing challenge. The use of superabsorbent polymers (SAP) has gained significant attention as a possible way to improve the performance of cement-based materials due to their unique water-absorption and retention properties. This study investigates the multifaceted impact of kaolin intercalation-modified superabsorbent polymers (K-SAP) on the properties of cement mortar. The results show that K-SAP significantly affects the cement mortar’s rheological behavior, with distinct phases of water absorption and release, leading to changes in workability over time. Furthermore, K-SAP alters the hydration kinetics, delaying the exothermic peak of hydration and subsequently modifying the heat release kinetics. Notably, K-SAP effectively maintains a higher internal relative humidity within the mortar, reducing the autogenous shrinkage behavior. Moreover, K-SAP can have a beneficial effect on pore structure and this can be ascribed to the internal curing effect of released water from K-SAP. [ABSTRACT FROM AUTHOR]

Stacking compacted filtered tailings has become an option to cope with the new Brazilian regulations while providing a safe disposal method for the tailings. It has become feasible due to recent developments in dewatering technologies. Still, the dewatering processes may need to be improved to attain acceptable moisture contents considering the on-field compactable range. Also, the filtered material's moisture content is highly influenced by the weather conditions, especially during the rainy season in the southeast of Brazil. Additives are a possible solution to accelerate moisture reduction. However, scientific studies in the technical literature still need to attest to the effectiveness of these methods to tailings, mainly on a full scale. Accordingly, the present research evaluates the performance of two additives to hasten filtered iron ore tailings drying for dry stacking purposes: commercially available quicklime and superabsorbent polymer. Also, undrained triaxial tests were conducted on specimens retrieved from on-field compacted layers to investigate the additive's influence on the tailings' mechanical behaviour. Initial confining pressures ranging from 100 to 600 kPa were used. The results have shown the inefficacy of the superabsorbent additives in boosting the drying process for on-field conditions and the efficiency of the quicklime in doing so. Furthermore, no substantial changes in the mechanical response were observed due to the insertion of quicklime. This highlights the novelty of the present study in the context of iron ore tailings management. [ABSTRACT FROM AUTHOR]

The leachate generation is an inevitable consequence of landfill disposal, and thus it is critically important to acquire effective approach to preventing contamination of the underlying soils and groundwater aquifers. Currently, there is no consensus on the best approach; the biological treatment and the membrane technology are widely tested but each has its own drawbacks. On the other hand, superabsorbent polymers are nowadays widely used in many liquid-absorbing applications but have rarely been assessed for the application of landfill leachate treatment. In this study, a comprehensive analysis of the physicochemical parameters, ionic parameters, and trace elements of the collected leachate was carried out, and four commercially available superabsorbent polymers with different chemical compositions were tested in respect of their kinetics of adsorption and desorption, both load-free and under-load, in deionized water, tap water, and leachate, respectively. The results are of significant importance in elucidating the application potential of commercially available superabsorbent polymers in landfill leachate treatment.

A composite's rheology can be changed by adding superabsorbent polymer (SAP) and basalt fibers and using silica fume. This study aimed to investigate the effects of these components on the viscosity and shear stress parameters of the paste. The proportions of the components were varied, with SAP content ranging from 0.01% to 0.03%, basalt fiber from 0% to 0.50%, silica fume (micro silica) at 15%, and water content from 0.40 to 0.50. Response surface methodology was used to optimize the mixture proportions, and the rheological properties of the resulting pastes were characterized using a rheometer. Results showed that the addition of SAP and basalt fiber had a significant impact on the rheological properties of the paste, with increasing amounts of both resulting in increased viscosity and shear stress. Overall, this study highlights the potential of SAP and basalt fiber in advances of the rheology of cement paste and provides insight into the optimal proportions of these components for achieving desired rheological properties. The findings of this study could be useful in developing high-performance concrete with enhanced rheological properties, which could have a wide range of applications in the construction industry. In addition, 0.50% BF, 0.01% SAP, and 0.445 water-to-cement were found as optimum proportions regarding the rheology of the cement paste.

The self-healing cement used in oil wells aims to provide long-term interlayer isolation by enabling the cement system to repair itself. This paper compared the absorption properties of 2-acrylamido-2-methyl propanesulfonic acid (AMPS)-based superabsorbent polymer (SAP) and acrylic acid (AA)-based SAP in water and cement slurry filtrate. The effect of cement slurry filtrate on the water absorption properties of the two SAPs was evaluated. The results showed that the calcium ions in the cement slurry would crosslink with the carboxyl groups in the AA-SAP, increasing the crosslink density and greatly reducing its absorption rate in water. Compared to AA-SAP, AMPS-SAP is more suitable for oil well cement slurries. AMPS-SAP can help reduce the fluid loss of cement slurry. The addition of 0.4% AMPS-SAP in cement slurry results in a 64 mL decrease in fluid loss. The properties (rheological properties, thickening time, and compressive strength) of cement slurry meet the requirements for well cementing construction. [ABSTRACT FROM AUTHOR]

The technology of seed coating with superabsorbent polymer (SAP) has the potential to mitigate the negative impact of drought on seed germination and crop establishment. However, their application on the seed surface can affect the effectiveness of pesticides used for seed treatment in the protection against phytopathogens. In our work, the influence of the Aquaholder®Seed polymer coating on the effectiveness of fungicides in the protection of germinating seeds of spring barley cv. Bojos and Laudis against the fungal pathogen Bipolaris sorokiniana was studied. One-half of the seeds were first treated with fungicides, and then a polymer was applied. Fungicide efficacy was evaluated in a Petri dish test and pot test under the pathogen attack. Seed coating with SAP did not negatively affect fungicide efficacy. The percentage of germinated seeds, seedling emergence, plant height, and symptoms of the disease in the fungicide-treated variants were not significantly changed by the SAP application. Moreover, in cv. Laudis, the application of SAP alone partially protected germinating seeds against pathogen attack. The amount of pathogen DNA in plant tissues of cv. Laudis was not significantly different among seed treatments, while in cv. Bojos, the pathogen DNA increased in seeds coated with SAP alone but decreased in combined treatment with fungicides. These results demonstrated that SAP seed coating does not negatively affect the efficacy of fungicides used for seed protection against fungal pathogens. [ABSTRACT FROM AUTHOR]