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Superabsorbent Composite (superabsorbent + composite)
Selected AbstractsStudy on Superabsorbent Composite, 14MACROMOLECULAR MATERIALS & ENGINEERING, Issue 12 2006Preparation of Poly(acrylic acid)/Organo-attapulgite Composite Hydrogels, Swelling Behaviors in Aqueous Electrolyte Solution Abstract Summary: Organo-attapulgite (organo-APT) was prepared by modifying APT using four quaternary ammonium salts with various lengths of the alkyl group, including (octyl)trimethylammonium bromide (OTMABr) and (stearyl)trimethylammonium chloride (STMACl), etc. A series of composite hydrogels, poly(acrylic acid)/organo-APT, from acrylic acid (AA), and organo-APT was prepared by aqueous polymerization, using N,N, -methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The organification and organification degree of APT as well as the corresponding composites were characterized by FTIR, TGA, and XRD. The effects of the length of the alkyl group for different quaternary ammonium salts, organification degree of APT, and organo-APT content on water absorbency and swelling behaviors in various electrolyte solutions were investigated in this study. Equilibrium water absorbency strongly depends on chain length of the alkyl group of quaternary ammonium salts, organification degree of APT as well as organo-APT content. Longer alkyl group, higher organification degree, and proper organo-APT content are of benefit for the improvement of equilibrium water absorbency. Equilibrium water absorbency in distilled water for PAA/APT was enhanced from 350.1 to 562.1 g,·,g,1 after 10 wt.-% organo-APT, modified with STMACl for the highest degree, was introduced. The kind of cation is the key factor influencing equilibrium water absorbency of these composite hydrogels in electrolyte solutions. Organification of APT could enhance responsiveness of the corresponding composite hydrogel to electrolyte solutions. Schematic structure of PAA/organo-APT composite in a dry state (left) and in a swollen state (right). [source] Study on superabsorbent composite XXV.POLYMER COMPOSITES, Issue 4 2010Synthesis, characterization, swelling behaviors of poly(acrylic acid- co - N -acryloylmorpholine)/attapulgite superabsorbent composites In this work, a novel poly(acrylic acid- co - N -acryloylmorpholine)/attapulgite superabsorbent composite was prepared by graft copolymerization among acrylic acid, N -acryloylmorpholine and attapulgite in aqueous solution, using N,N, -methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The result from FTIR spectra showed that OH of attapulgite participated in graft copolymerization with acrylic acid and N -acryloylmorpholine. Proper monomer ratio and atapulgite content could form a loose surface, and improve reswelling ability and initial swelling rate. The buffer action of the COOH and COO, groups in the superabsorbent composite keeps the water absorbency a rough constant in the pH range of 4.4,9.6. Both polarity and structure of an organic solvent are responsible for the phase transition point of the superabsorbent composite. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Study on superabsorbent composite.POLYMER COMPOSITES, Issue 8 2009In this work, the effects of different cation-exchanged montmorillonite on water absorbency of poly(acrylic acid- co -acrylamide)/montmorillonite/sodium humate (PAA-AM/MMT/SH) superabsorbent composite were systematically investigated under the same preparation conditions. The superabsorbents doped with different cation-exchanged montmorillonite were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy technologies. Swelling behaviors of developing superabsorbent composite in various cationic saline solutions (NaCl, CaCl2, and FeCl3) were also investigated. The water absorbencies of superabsorbent composite with 20 wt% MMT and 30 wt% SH are 638, 723, 682, and 363 g g,1 in distilled water for incorporating natural Na+ -MMT, Li+ -exchanged MMT, Ca2+ -exchanged MMT, and Al3+ -exchanged MMT, respectively. The results showed that the cation-exchange process had some obvious influences on final water absorbency of superabsorbent composite. NaCl, CaCl2, and FeCl3 solutions did not alter the swelling characteristics of the superabsorbent materials at a concentration of less than 0.01 mM, however, a concentration of greater than 0.1 mM caused a collapse in the swelling curves. The excellent swelling-reswelling-swelling behavior and lower swelling rate testified that Al3+ -exchanged MMT can act as an assistant crosslinker in the polymeric network. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Influence of the COOH and COONa groups and crosslink density of poly(acrylic acid)/montmorillonite superabsorbent composite on water absorbencyPOLYMER INTERNATIONAL, Issue 9 2001Jihuai Wu Abstract A novel poly(acrylic acid)/montmorillonite superabsorbent composite with a water absorbency of 1100 times its own weight was synthesized by the graft copolymerization of acrylic acid with a cross-linking agent in the presence of montmorillonite ultrafine powder. The influence of the amount of crosslinker and montmorillonite on water absorbency has been investigated. It was found that a crosslinker concentration of 0.03,wt% and 30,wt% montmorillonite gave the best results. The collaborative absorbent effect of sodium carboxylate and carboxylic acid groups was superior to that of sodium carboxylate or carboxylic acid groups alone, and the composite with a ratio of about 2/3 for sodium carboxylate to carboxyl acid groups possessed the highest water absorbence. © 2001 Society of Chemical Industry [source] Preparation and swelling behavior of amphoteric superabsorbent composite with semi-IPN composed of poly(acrylic acid)/Ca-bentonite/poly(dimethyldiallylammonium chloride)POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2007Liuchun Zheng Abstract Amphoteric superabsorbent composite with semi-interpenetrating polymer networks (semi-IPN) composed of poly(acrylic acid) (PAA)/Ca-bentonite/poly(dimethyldiallylammonium chloride) (PDMDAAC) was prepared by a combination of intercalative polymerization and a sequential IPN method and the effects of reaction parameters on the swelling capacity were studied. PDMDAAC was used as a polycation to modify bentonite and form semi-IPN with lightly crosslinked PAA. FTIR and TG were used to characterize the amphoteric superabsorbent composites with semi-IPN. The thermal stability of the product was not degraded as in the case of using small molecular surfactant to modify bentonite. The contents of carboxylic groups and nitrogen had been determined. This indicated that the product with certain content of carboxylic groups and nitrogen is inclined to exhibit excellent swelling capacity. The presence of PDMDAAC improved the swelling capacity. The resulting amphoteric superabsorbent composite showed excellent swelling capacity of 1578,g/g in distilled water and 136,g/g in 0.9,wt% NaCl solution. Copyright © 2007 John Wiley & Sons, Ltd. [source] Preparation, swelling behaviors and application of polyacrylamide/attapulgite superabsorbent compositesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2006Junping Zhang Abstract A series of superabsorbent composites, polyacrylamide/attapulgite (PAMA), were prepared from acrylamide (AM) and attapulgite micropowder in aqueous solution, using N,N,-methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator and then saponified with sodium hydroxide solution. This paper focuses on swelling behaviors of the PAMA superabsorbent composites in various saline solutions. The results indicate that saline solutions can weaken the swelling abilities of the PAMA compsites greatly. Water absorbency of the PAMA composites with 20 and 40,wt% attapulgite in aqueous chloride salt solutions has the following order: Li+,=,Na+,=,K+, Mg2+,>,Ca2+,=,Ba2+ all through the range of concentration investigated. However, swelling properties of the composites are complicated in CuCl2(aq), AlCl3(aq) and FeCl3(aq) solutions and are related to saline solutions concentration. The deswelling behavior of PAMA composites is more obvious in univalent chloride salt solutions than in divalent and trivalent ones. The influence of kind and valence of anions on swelling ability of the composites is limited and almost the same. Moreover, reswelling capability, practical water retention ability in sand soil of the composites and the effect of pH on water absorbency of the PAMA composites were investigated. The PAMA composite shows good water retention and reswelling ability in sand soil, and may be used as a recyclable water-managing material for the renewal of arid and desert environment. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||