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Glycerol acrylate (GA) is synthesised by an acryloylation reaction with acryloyl chloride. An ester was used as a cross-linking agent at varying proportions in the synthesis of poly acrylic acid (PAA). The amount of cross-linking density in the product (GA-PAA) and degree of neutralisation determine the absorbency of the polymer samples. A sample of GA-PAA containing 0.8 % GA was discovered to absorb 395 and 66 g/g of water and saline solution, respectively. Different solvent uptakes were tested with the sample showing varying capacity for different solvents. The temperature of the reaction was maintained at 60 °C and a reaction time of 2½ h. FTIR, TGA, SEM and XRD analyses were used to characterise the products. [ABSTRACT FROM AUTHOR]

• SAP was synthesized using kaolin through inverse suspension polymerization. • New SAP reveals satisfactory physical and mechanical performances. • Use of kaolin enhanced the rigid network of new SAP while reducing its cost. • The increase in the acrylamide content led to a greater final equilibrium absorbency rate of new SAP. The water absorption of ionic SAP in cement-based materials is small. Therefore, this study synthesized a low-grade kaolin-enhanced SAP through inverse suspension polymerization, and its performances in deionized water, the saturated Ca(OH) 2 solution and the supernatant of the cement slurry were investigated. The results indicate that the synthesized SAP revealed a spherical shape with a uniform particle size, showing well dispersion after water saturation. In addition, the use of low-grade kaolin could be beneficial concerning the absorbency of SAP especially using 7.5% low-grade kaolin, as reflected by the consistency results, but its absorbency is sensitive to water temperatures and environmental relative humidity. Besides, compounding inorganic materials into SAP can reduce the cost of SAP synthesis and provide cost efficiency. Finally, the growth of the acrylamide content could deteriorate the absorbency of SAP, but their final equilibrium absorbency could increase, and the absorbency of the synthesized SAP were similar in the media of the saturated Ca(OH) 2 solution and the supernatant of cement slurry. [ABSTRACT FROM AUTHOR]

Unique polypyrrole (PPy) hydrogels are prepared by using orange IV as the dopant and FeCl as the oxidant. The static polymerization of pyrrole monomer in aqueous solution is accompanied with self-assembly of PPy hydrogel. PPy hydrogels not only show good electrical conductivities, but also exhibit excellent water-absorbent behaviors. The macroscopic appearance, microscopic morphology and water-absorbent behaviors of PPy hydrogels can be controlled by the choice of the reaction condition. The effects of ionic strength on the physical properties of PPy hydrogels are also studied. The results indicate that PPy hydrogels show improved water absorbencies in saline solution. Moreover, PPy hydrogel is used as an efficient adsorbent to remove Cr(VI) from aqueous solutions. PPy hydrogel exhibits much better adsorption performance than common PPy nanoparticles. This kind of PPy hydrogel is expected to be a potential candidate for water treatment. [ABSTRACT FROM AUTHOR]

In this study, nano-fibrillated cellulose (NFC) was added during the UV-induced polymerization process of acrylic acid, so that the resulting poly-(acylic acid)/NFC composites can have improved water absorbency and swelling rate. The effects of process parameters, including NFC content on the UV-induced polymerization process, and the properties of resulting PAA hydrogel/NFC composites were investigated. Results showed that the addition of a small amount of NFC led to significant increase in both water absorbency and swelling rate of the PAA hydrogel/NFC composites. When compared to the control (without the addition of NFC), the water absorbency of the resulting PAA hydrogel/NFC composites increased from 380 to 525 g/g at 1 wt% of NFC addition (based on the dry weight of acrylic acid), while the swelling rate in deionized water and 0.9 % NaCl solution increased by 17.6 and 25.0 %, respectively. The results indicated that the PAA hydrogel/NFC composites were very promising for industrial application. [ABSTRACT FROM AUTHOR]

The Superabsorbent resin was synthesized based on poly(ethylene glycol) methacrylate (PEGMA), acrylic acid(AA) and acrylamide(AM) by inverse suspension polymerization. By plenty of trial and error in previous works, we used mono-octadecyl phosphate as the dispersant to stabilize the suspension system effectively. In addition, the monomer we employed, PEGMA, also took a role as dispersant, this resulted in the shortage of mono-octadecyl phosphate to reduce the consumption of raw materials effectively. The effects of temperature, the concentration of monomers, the dosage of initiator, crosslinking agent and marcomonomer on the absorbency were studied. At the same time, the kinetics of swelling also was studied. The maximum absorption of the resin reached 930 mL/g and 94 mL/g for deionized water and 0.9 wt % NaCl solution, respectively. [ABSTRACT FROM AUTHOR]