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Ionic Groups (ionic + groups)
Selected AbstractsMolecular Design of Superabsorbent Polymers for Organic Solvents by Crosslinked Lipophilic Polyelectrolytes,ADVANCED FUNCTIONAL MATERIALS, Issue 24 2008Toshikazu Ono Abstract Molecular design of lipophilic polyelectrolyte gels as superabsorbent polymers that exhibit a high degree of swelling in less-polar and nonpolar organic solvents is demonstrated. A small amount of tetraalkylammonium tetraphenylborate with long alkyl chains as a lipopholic ion pair is incorporated into crosslinked polyacrylates with variable alkyl chain lengths to provide novel lipophilic polyelectrolyte gels. Their swelling degree becomes more than 100 times as much as their dried weights in various organic solvents. The high effectiveness of the swellable solvents shifts to the polar ones by decreasing the length of the alkyl chain. Swelling or collapsing of the lipophilic polyelectrolyte gels originates from both incompatibility of the polymer chains in the media and dissociation of ionic groups. Thus, a unique superabsorbency is observed when the polymer chains have good compatibility with the solvents and the solvents have relatively high polarities enough to dissociate the ionic groups. By varying the polarity of the neutral monomer in these polyelectrolyte gels, the design of gels that can absorb solvents of nearly any polarity is demonstrated. [source] Preparation and adsorption behavior of a cellulose-based, mixed-mode adsorbent with a benzylamine ligand for expanded bed applicationsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Dong Gao Abstract A novel mixed-mode expanded bed adsorbent with anion-exchange properties was explored with benzylamine as the functional ligand. The cellulose composite matrix, densified with stainless steel powder, was prepared with the method of water-in-oil suspension thermal regeneration. High activation levels of the cellulose matrix were obtained with allyl bromide because of the relative inertness of the allyl group under the conditions of the activation reaction. After the formation of the bromohydrin with N -bromosuccinimide and coupling with benzylamine, the activated matrix was derived to function as a mixed-mode adsorbent containing both hydrophobic and ionic groups. The protein adsorption capacity was investigated with bovine serum albumin as a model protein. The results indicated that the prepared adsorbent could bind bovine serum albumin with a high adsorption capacity, and it showed salt tolerance. Effective desorption was achieved by a pH adjustment across the isoelectric point of the protein. The interactions between the cell and adsorbent were studied, and the bioadhesion was shielded by the adjustment of the salt concentration above 0.1M. Stable fluidization in the expanded bed was obtained even in a 2% (dry weight) yeast suspension. The direct capture of target proteins from a biomass-containing feedstock without extra dilution steps could be expected with the mixed-mode adsorbent prepared in this work, and this would be especially appropriate for expanded bed adsorption applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Ionic Polymer-Metal Composite Actuators Employing Radiation-Grafted Fluoropolymers as Ion-Exchange MembranesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2006Man Jae Han Abstract Summary: To develop ionic polymer-metal composites (IPMC) with improved performance, three new ion-exchange membranes were prepared and employed in IPMC construction. The membranes were prepared by radiation-grafting of polystyrene sulfonic acid onto three fluoropolymers; poly(vinylidenefluoride- co -hexafluoropropylene), poly(ethylene- co -tetrafluoroethylene), and poly(tetrafluoroethylene- co -hexafluoropropylene). The bending displacements of the IPMCs constructed with these membranes were at least several times larger than that of Nafion IPMC of similar thickness without straightening-back. The larger displacement was considered to be due to the higher concentration of ionic groups and consequent larger ion-exchange capacity. Actuation of (a) Nafion IPMC and (b) IPMC prepared in this study. [source] A new crystalline phase of nitric acid dihydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2001Nathalie Lebrun The crystal structure of a new high-temperature phase of nitric acid dihydrate, HNO3·2H2O, has been determined at 225,K by single-crystal X-ray diffraction. The H atom of the nitric acid is delocalized to one water molecule, leading to an association of equimolar NO3, and H5O2+ ionic groups. The asymmetric unit contains two molecules of HNO3·2H2O. The two independent molecules are related by a pseudo-twofold c axis, by a translation of 0.54 (approximately ½) along b, with a mean atomic distance difference of 0.3,Å, except for one H atom of the water molecules (1.5,Å), because of their different orientations in the two molecules. The two independent molecules, linked by strong hydrogen bonds, are arranged in layers. These layers are linked by weaker hydrogen bonds oriented approximately along the c axis. A three-dimensional hydrogen-bond network is observed. [source] | ||||||||||