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Quaternary Ammonium Groups (quaternary + ammonium_groups)
Selected AbstractsAntibacterial activity of novel insoluble bead-shaped polymer-supported multiquaternary ammonium saltsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010E. Murugan Abstract This study describes the effect of antibacterial activity of newly reported five different novel insoluble bead-shaped polymer-supported multiquaternary ammonium salts (PM quats) viz., bis-quat, tris-quat (2 Nos.), tetrakis-quat, hexakis-quat containing two, three, four, and six quaternary ammonium groups, respectively. The presence of number of quaternary ammonium groups in each salt was established already through Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and chloride ion analyzes. The antibacterial activities of these five different PM quats against three different bacteria viz., Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa were investigated by serial dilution and spread plate method and compared the same with a monoquat containing single quaternary ammonium group. The extent of antibacterial activity has been measured in terms of colony forming units (CFU) at different time intervals. The observed results show that all the PM quats exhibited excellent-antibacterial activity against each bacterium. On the basis of the CFU values, the antibacterial activity was found to increase from bis-quat to hexakis-quat, which reveals that the activity of PM quats increases with increase in the number of quaternary ammonium groups. The mechanism of interaction of quats with bacterial cytoplasmic membrane has been explained as an adsorption-like phenomenon. The reusability of highly active hexakis-quat against Staphylococcus aureus was studied and the activity was found to reduce after first cycle. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effective preparation and characterization of montmorillonite/poly(,-caprolactone)-based polyurethane nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Eun Hwan Jeong Abstract In this study, montmorillonite (MMT)/poly(,-caprolactone)-based polyurethane cationomer (MMT/PCL-PUC) nanocomposites were prepared and their mechanical properties, thermal stability, and biodegradability were investigated. PCL-PUC has 3 mol % of quaternary ammonium groups in the main chain. The MMT was successfully exfoliated and well dispersed in the PCL-PUC matrix for up to 7 wt % of MMT. The 3 mol % of quaternary ammonium groups facilitated exfoliation of MMT. The 1 wt % MMT/PCL-PUC nanocomposites showed enhanced tensile properties relative to the pure PCL-PU. As the MMT content increased in the MMT/PCL-PUC nanocomposites, the degree of microphase separation of PCL-PUC decreased because of the strong interactions between the PCL-PUC chains and the exfoliated MMT layers. This resulted in an increase in the Young's modulus and a decrease in the elongation at break and maximum stress of the MMT/PCL-PUC nanocomposites. Biodegradability of the MMT/PCL-PUC nanocomposites was dramatically increased with increasing content of MMT, likely because of the less phase-separated morphology of MMT/PCL-PUC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Characterization of anion-exchange membranes containing pyridinium groupsAICHE JOURNAL, Issue 12 2003Moon-Sung Kang A poly(vinyl chloride) (PVC)/glycidyl methacrylate (GMA)-divinyl benzene (DVB)-based membrane was prepared via monomer sorption, and then pyridium or its derivates (that is, 4-ethyl pyridium, 4-tetrabutyl pyridium) were introduced into the PVC/poly(GMA-DVB) base membrane. The effects of pyridinium anion-exchangeable sites on the water splitting and the electrochemical properties of the membrane were investigated. The electrochemical properties and the water splitting on the anion-exchange membranes were compared with selected commercial membranes containing quaternary ammonium groups. The pyridium membranes showed good electrochemical properties, comparable to those of the commercial membranes, with electrical resistances of less than 3.0 × 10,4 ,·m2 in 0.5 mol dm,3 NaCl and high ionic permselectivities (the transport number of Cl, ions being 0.96). Moreover, water splitting indicated by the proton transport numbers of the membranes containing pyridinium or its derivates, were about two or three orders of magnitude lower than those of the commercial membranes (such as AM-1) at the same current density because the resonance effect in the quaternary pyridinium groups contributed to their molecular stability. [source] Bile acid sequestrants based on cationic dextran hydrogel microspheres.JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2001Abstract Cationic dextran hydrogel microspheres with pendant quaternary ammonium groups having alkyl substituents (C2,C12) at quaternary nitrogen were synthesized. The in vitro sorption of sodium salts of four bile acids (glycocholic, cholic, taurocholic, and deoxycholic acids) with these hydrogels was studied as a function of substituent alkyl chain length and bile acid hydrophobicity. Sorption experiments were performed in phosphate buffer solutions (pH 7.4) containing one bile salt (individual sorption) or mixtures of several bile salts (competitive sorption). Parameters for individual sorption were calculated taking into consideration the stoichiometric and cooperative binding of bile salts to oppositely charged polymer hydrogels. The results show that the increase in the length of the alkyl chain of the substituent leads to an increase in both ionization constant K0 and overall stability constant of binding K, but decreases the cooperativity parameter u. The competitive sorption studies indicate that the hydrogels display a good affinity for both dihydroxylic and trihydroxylic bile salts. The molar ratio of maximum amounts bound for the two types of bile acid is 2 to 1, which is much lower than those reported for other cationic polymers recommended as bile acid sequestrants. The binding constants for the sorption of bile salts by some dextran hydrogels are 20,30 times higher than those obtained for cholestyramine under similar sorption conditions. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:681,689, 2001 [source] PS/PMMA mixed polymer brushes on the surface of clay layers: Preparation and application in polymer blendsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2007Jian Zhang Abstract Polystyrene (PS) and poly(methyl methacrylate) (PMMA) mixed polymer brushes on the surface of clay layers were prepared by using in situ free radical polymerization. Free radical initiator molecules with two quaternary ammonium groups at both ends were intercalated into the interlayer spacing of clay layers. The amount of polymer brushes grafted on the surface of clay layers can be controlled by controlling the polymerization time. Thermogravimetric analysis, X-ray diffraction, and high-resolution transmission electron microscope results indicated successful preparation of the mixed polymer brushes on the surface of clay layers. The kinetics of the grafting of the monomers was also studied. The mixed polymer brushes on the surface of clay layers were used as compatibilizers in blends of PS and PMMA. In the blends, the intercalated clay particles tend to locate at the interface of two phases reducing the interfacial tension. In the meanwhile, PMMA homopolymer chains tend to intercalate into clay layers. The driving force for the intercalation is the compatibility between homo-PMMA chains and PMMA brushes on the surface of clay layers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5329,5338, 2007 [source] Switchable thin-film surface prepared via a simple grafting-to method using a polystyrene- b -poly(2-vinylpyridine) copolymerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2006Ying Wang Abstract A polystyrene- b -poly(2-vinylpyridine) block copolymer containing a methylhydridosilane linking group was chemically grafted to an 8-trichlorosilyloctene monolayer via a simple one-step hydrosilylation reaction. The resulting Y-shaped thin film exhibited a low grafting density, which was characteristic of the grafting-to technique. To further reduce the miscibility of the two arms, methyl iodide was reacted with the poly(2-vinylpyridine) block to produce quaternary ammonium groups. The surfaces before and after quaternization were both solvent-switchable when subjected to block-selective solvents. Tensiometry, ellipsometry, attenuated total reflection/Fourier transform infrared, and atomic force microscopy were used to characterize the properties and morphology of both unquaternized and quaternized samples. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5608,5617, 2006 [source] Application of a fibre-reactive chitosan derivative to cotton fabric as a zero-salt dyeing auxiliaryCOLORATION TECHNOLOGY, Issue 3 2004Sang-Hoon Lim Cotton fabric has been treated with a fibre-reactive chitosan derivative containing quaternary ammonium groups, O -acrylamidomethyl- N -[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride (NMA-HTCC). Cotton treated with NMA-HTCC has been dyed with direct and reactive dyes without the addition of salt. The colour yield was higher than that on untreated cotton, despite the addition of a large amount salt in the latter case. After dyeing, cotton treated with NMA-HTCC gave better wash fastness than the untreated cotton. The light fastness was however inferior to that on untreated cotton. The antimicrobial activity of cotton treated with NMA-HTCC against Staphylococcus aureus was considerably lower after dyeing, probably due to the antimicrobial effect of the cationic group on NMA-HTCC being blocked by its combination with the anionic dye. [source] | |||||||||||||