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Modified MIL‐101(Al)‐NH2 (MIL‐101(Al)‐NH2‐net) is used as a crosslinking agent and acrylic acid (AA) as a monomer, the MIL‐101(Al)‐NH2‐net grafted polyacrylic acid (MIL‐101(Al)‐NH2‐net‐g‐PAA (MAP)) composite water‐absorbent material is synthesized using the free radical polymerization method to study the application of composite absorbent materials in water collection. The structure and morphology of the composite water‐absorbent material are characterized using Fourier transform infrared spectrometry (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer Emmett Teller (BET), and thermogravimetric analysis (TG), and the contents of ammonium persulfate (APS), MIL‐101(Al)‐NH2‐net, and neutralization degree of AA are optimized. Under optimal conditions, the water absorption ratios of the composite materials in distilled water, tap water, and 0.9% NaCl solution are 744, 169.5, and 85.5 g g−1. In addition, the properties of collecting water vapor are investigated. At 25 °C, 50% Relative Humidity (RH), 70% RH, and 90% RH, the MAP water vapor adsorption capacity is 0.0312, 0.5760, and 1.6856 g g−1, respectively. The water vapor adsorption of MIL‐101(Al)‐NH2 and MIL‐101(Al)‐NH2 self‐polymerization products are 0.025 and 0.1278 g g−1, respectively. The result showed that autopolymerization can improve the water vapor adsorption performance. [ABSTRACT FROM AUTHOR]

The protein‐based superabsorbent composite FCP‐g‐PAA/Kaolinite is prepared by grafting acrylic acid (AA) into the flax cake protein (FCP) using free radical polymerization in this study. The chemical structure, thermal stability, and the morphology of the FCP‐g‐PAA/Kaolinite are characterized by Fourier transform infrared, Thermogravimetric analysis, and scanning electron microscope. The results show that AA was grafted successfully into FCP. And, it has the maximum swelling capacity where the MBA concentration, APS concentration, Kaolinite concentration, FCP concentration, neutralization degree, and reaction time was 0.13%, 1.4%, 8%, 9%, 70% and 2 h, respectively. The swelling capacity reaches 860 g/g in distilled water, 238 g/g in tap water and 78 g/g in 0.9% NaCl. In addition, its water absorbency can still reach 60% after reuse for six times and the water retention rate of the material was 70% after 12 h. Therefore, FCP has a broad application prospect as a material for preparing superabsorbent composite. [ABSTRACT FROM AUTHOR]

A sesbania gum‐g‐poly (acrylic acid‐co‐vinyl acetate) (SG‐g‐P (AA‐co‐VAc)) emulsion was prepared by free radical polymerization using environmental‐friendly sesbania gum (SG) as raw material and grafted with acrylic acid and vinyl acetate. It was applied to study the performance of preventing water leakage from the soil. The effects of acrylic acid/vinyl acetate (AA/VAc) monomer ratio, neutralization degree of AA, content of ammonium persulfate and polymerization temperature on the properties of emulsion were investigated. Characterization of the emulsion by FTIR, SEM, TGA, and particle size distribution showed that AA and VAc were successfully grafted onto SG. SG‐g‐P (AA‐co‐VAc) had good stability under the optimum synthesis condition. Compared to SG, the thermal stability of the product was improved. The consolidation layer was formed after the product was added to the soil, which might reduce the voids between soil particles and reduce the water penetration rate. This greatly expanded its application in the research of anti‐leakage performance. [ABSTRACT FROM AUTHOR]

Temperature/pH-responsive hydrogels are one of the most studied environmental-responsive hydrogels, with sensitivity and rapid response being the sought-after properties, while sensitivity and reusability are generally poor. This study prepared a hydrogel with a temperature/pH-responsive core-shell structure by static template polymerization, using the temperature-sensitive monomer dimethylaminoethyl methacrylate polymerized with 2-acrylamide-2-methylpropanesulfonic acid as the temperature-sensitive shell and popcorn with acrylic acid as the pH-responsive core-layer hydrogel. The chemical structure, thermal stability, and morphology of the core-shell structure hydrogels were characterized by Infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller surface (BET), Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Thermogravimetric analysis (TG), respectively. The pH responsiveness well as the temperature responsiveness of the shell structure was tested. The results showed that the lowest critical solution temperature (LCST) of the core-shell hydrogel is 43 ℃, with good temperature responsiveness in the range of 25–55 ℃, pH responsiveness from pH= 4 to pH= 13, and a short response time. From SEM, AFM, and BET, it can be concluded that the hydrogel has a rough surface and pore structure with a root mean square roughness value of 0.787 nm, a specific surface area of 1.3381 m²/g, and an average pore size of 4.0911 nm. FTIR and XRD can show that popcorn (PCP) is well-doped in the core-shell structure hydrogel, which also proves the existence of the core-shell structure. The design of the core-shell structure enhanced the stability performance of the shell temperature-sensitive hydrogel so that the retention rate of the sample was still 37% at 800 °C, and the water retention rate was still 80.7% after repeated immersion in distilled water 7 times, which has good prospects for agricultural and pharmaceutical applications. [Display omitted] • In this experiment, a static template polymerization method was used to synthesize the core-shell structure hydrogel, which is simple to operate and can be mass-produced. • The addition of popcorn enhances the porosity of the core layer hydrogel and facilitates the entry of water. • The preparation of the core-shell structure makes the hydrogel better adapted to the high temperature and high salt environment required for plant growth. • The preparation of core-shell structured hydrogels enhances the reusability and thermal stability of hydrogels. [ABSTRACT FROM AUTHOR]

There have been a lot of reports on the preparation and properties of superabsorbent polymers, but there are still some problems and limitations in practical application. Therefore, a superabsorbent polymer (SAP) was synthesized by solution polymerization with tap water as reaction medium, acrylic acid and cross-linked polyvinylpyrrolidone (PVPP) as raw materials. The results of its performance and application show that the particle size was 0.425–0.85 mm, and the maximum water absorption rate of SAP in distilled water, tap water and 0.9% wt% NaCl solution was 2297 g/g, 333 g/g and 120 g/g, respectively. The water absorption rate can reach about 80% of maximum water absorption rate in 30 min. In addition, when the SAP mass addition amount was 0.56% and the particle size was 0.15–0.25 mm, the saturated moisture of sandy soil increased by 187%, the infiltration rate of sandy soil decreased by 96.7% and at 45 °C and 25 °C, the water evaporation rate of sandy soil decreased by 57.52% and 43.61%, respectively. So the material have a good application prospect in desertification and agriculture, and the way of preparation can be more effectively applied in practical production. [Display omitted] (a) The flowchart of SAP preparation; (b) The schematic diagram of the application of SAP in sandy soil; (c) The schematic diagram of cage effect. • The performance of SAP is improved from a new perspective that is reaction medium. • The addition of SAP can effectively increase the performance of soil. • The material has excellent water absorption and water retention. • The presence of ions would affect the effect of initiator and shorten the gel time of SAP. [ABSTRACT FROM AUTHOR]

In order to reduce the pollution of the bio-waste cabbage to the environment and achieve recycling of biological waste resources, synthesis of a novel superabsorbent polymer gel based on waste cabbage (CB) using two monomers AMPS (2-acrylamide-2-methyl-1-propane sulfonic acid) and AA (acrylic acid). And the synthesis conditions were optimized, such as the ratio of AMPS and AA, initiator content, and crosslinker content. And the water retention, salt resistance and repeated swelling performance were investigated too. The chemical structure thermal stability and microscopic appearance of the superabsorbent polymer gel were investigated by Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric analysis (TGA) and Scanning electron microscope (SEM). The results showed that the novel superabsorbent polymer gel exhibits excellent water absorbency, which can absorb ultrapure water, distilled water, tap water and 0.9% NaCl solution are 1914 g/g, 1726 g/g, 306 g/g and 114 g/g, respectively. This is higher than in related studies 30%− 40% in distilled water, 60%− 70% in tap water and 10%− 20% in 0.9% NaCl solution. Therefore, this superabsorbent polymer gel showed a high swelling property and stable salt resistance. It has a broad application prospect. [Display omitted] • A novel SAP synthesized using waste cabbage. • Provides a new way to utilize this resource. • SAP with excellent water absorption performance. • Synthesis using a simple and effective method. [ABSTRACT FROM AUTHOR]