Poly(aminomethoxypropylacrylamide)

In this study, a temperature sensitive polymer was obtained by the solution polymerization of 2-amino-1-methoxypropylacrylamide. The monomer, 2-amino-1-methoxypropylacrylamide was synthesized by the nucleophilic substitution reaction of N-2-amino-1-methoxypropane and acryloyl chloride. The solution polymerization was performed in ethanol at 70 degrees C by using azobisisobutyronitrile as the initiator. Poly(2-amino-1-methoxypropylacrylamide). PAMPA, exhibited a reversible phase transition behavior by the temperature in the aqueous medium. The effects of polymer and salt concentrations on the lower critical solution temperature and critical flocculation temperature were investigated. The lower critical solution temperature values were 56.5, 46.5, 43.5 and 35.0 degrees C for 0.1, 0.5, 1.0 and 5.0 wt.% PAMPA solutions in aqueous media, respectively. These results indicated that lower critical solution temperature is dependent on the polymer concentration. It was also found that critical flocculation temperature for 0.1 wt.% PAMPA concentration decreased from 52.5 degrees C to 35.0 degrees C and for 1.0 wt.% PAMPA from 47.5 degrees C to 28.5 degrees C in salt concentrations. The effect of salt concentration on the critical flocculation temperature of poly(2-amino-1-methoxypropylacrylamide) was reasonably similar to that of poly(isopropylacrylamide). In ethanol-water media, the reversible phase transition behavior was observed up to the ethanol concentration of 30% (v/v). This study indicated that poly(2-amino-1-methoxypropylacrylamide) was an alternative thermally reversible material for poly(isopropylacrylamide). (C) 2010 Elsevier B.V. All rights reserved

chromium(VI) ions

The polyethyleneglycolmethacrylate-co-vinylimidazole (PEGMA-VI) copolymers, that can be used in heavy metal removal applications, were synthesized and characterized; and their use as sorbents in heavy metal removal was investigated. It was determined that the ligand vinylimidazole was successfully inserted into the polymer structure. Then, chromium (Cr(VI)) and nickel (Ni(II)) ions were used as model species to investigate the usability of the obtained microspheres in heavy metal removal. The effects of pH of the adsorption medium, initial concentration of the metal ions and VI content of PEGMA-VI microspheres were investigated as the effective parameters on the adsorption capacities of the microspheres. The adsorption rate of the microspheres was also investigated for determination of the optimum adsorption time which is the required time for maximum adsorption capacity. The adsorption capacities under optimum conditions were also determined. The order of adsorption affinities of PEGMA-VI microspheres with respect to the used metals was determined by competitive adsorption studies. According to the obtained results, the highest adsorption affinity of the PEGMA-VI microspheres was towards Cr(VI) ions, the adsorption affinity was less for Ni(II) and the least affinity was towards Cu(II) ions. The adsorption-desorption studies showed that the microspheres were reusable without a significant decrease in the ion adsorption capacities. (C) 2009 Elsevier B.V. All rights reserved

transfer polymerization

An ion-exchanger with polyanionic molecular brushes was synthesized by a "grafting from" route based on "surface-controlled reversible addition-fragmentation chain transfer polymerization" (RAFT). The RAFT agent, PhC(S)SMgBr was covalently attached to rnonodisperse-porous poly(dihydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(DHPM-co-EDM) particles 5.8 mu m in size. The monomer, 3-sulfo-propyl methacrylate (SPM), was grafted from the surface of poly(DHPM-co-EDM) particles with an immobilized chain transfer agent by the proposed RAFT protocol. The degree of polymerization of SPM (i.e. the molecular length of the polyanionic ligand) on the particles was controlled by varying the molar ratio of monomer/RAFT agent. The particles carrying polyanionic molecular brushes with different lengths were tested as packing material in the separation of proteins by ion exchange chromatography. The columns packed with the particles carrying relatively longer polyanionic ligands exhibited higher separation efficiency in the separation of four proteins. Plate heights between 130-200 mu m were obtained. The ion-exchanger having poly(SPM) ligand with lower degree of polymerization provided better peak-resolutions on applying a salt gradient with higher slope. The molecular length and the ion-exchanger group content of polyionic ligand were adjusted by controlling the degree of polymerization and the grafting density, respectively. This property allowed control of the separation performance of the ion-exchanger packing

removal

Polyethyleneglycolmethacrylate (PEGMA) and vinylimidazole (VI) were used in order to obtain microspheres of PEGMA-VI copolymers that can be used in heavy metal removal applications. The obtained copolymers were characterized and their use as sorbents in heavy metal removal was investigated. In the first part of the study, PEGMA-VI microspheres were prepared by suspension polymerization method. The obtained swellable microspheres with 10-50 mu m average diameter did not have permanent porosity according to the morphological and physicochemical determinations. The sizes of microspheres became smaller with increasing VI and cross-linker ethyleneglycoldimethacrylate (EGDMA) contents and increasing agitation rate. The VI content, EGDMA ratio, pH and ionic strength were determined as the effective parameters on the swelling behavior of PEGMA-VI microspheres. In the second part of the study, Cu(II) ions were used as a model species in order to investigate the usability of the obtained PEGMA-VI microspheres in heavy metal removal. Adsorption capacities under optimum conditions were determined. The Cu(II) ion adsorption capacity increased by increasing the initial Cu(II) ion concentration, and it reached the maximum value (i.e., 30 mg Cu(II)/g PEGMA-VI microspheres) at 400 mg Cu(II)/L initial Cu(II) ion concentration under the determined optimum conditions. Microspheres were found to be reusable after desorption for several times. (C) 2008 Elsevier B.V. All rights reserved

stationary phase

A new class of monodisperse macroporous beads in the hydrophilic form were synthesized by seeded microsuspension copolymerization of two acrylic crosslinking agents, glycerol dimethacrylate (GDMA) and glycerol-1,3-diglycerolate diacrylate (GDGDA). The monodisperse porous poly(glycerol dimethacrylate-co-glycerol-1,3-diglycerolate diacrylate), poly(GDMA-co-GDGDA) beads were highly hydrophilic in nature due to hydroxyl functionality resulting from both crosslinking agents. The beads with different particle sizes between 4.5 and 6.7 mu m and with different porous properties were obtained by changing the seed latex to monomer ratio. The bead size decreased, the average pore size increased and the specific surface area decreased with increasing seed latex to monomer ratio. Poly(GDMA-co-GDGDA) beads were slurry packed in microbore and semimicro-HPLC columns and successfully used as a stationary phase in aqueous size exclusion chromatography (SEC) mode in a micro-liquid chromatography system. The aqueous SEC runs were performed by using dextran standards in the molecular weight range of 1000-670,000 Da. SEC calibration curves exhibiting linearity in a wider range of molecular weight were obtained with the semi-micro and micro-HPLC columns packed with the poly(GDMA-co-GDGDA) beads synthesized with the seed latex to monomer ratios of 0.038 and 0.058 g/mL. The dextran standards could be eluted in an analysis time shorter than 2 min using micro or semi-micro columns packed with poly(GDMA-co-GDGDA) beads as stationary medium. These packings are suitable for molecular weight determination between 5 x 10(3) and 5 x 10(5) Da in the aqueous medium by using mobile phase flow rates in the range of 25-250 mu L/min. The average molecular weight determinations of different water soluble polymers, an ionic polymer, poly(2-dimethylaminoethyl methacrylate), a zwitterionic polymer, poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide), and a non-ionic polymer. poly(vinyl alcohol) were performed on a semimicro-column packed with the poly(GDmA-co-GDGDA) beads. Satisfactory results were obtained in the molecular weight determination of hydrophilic polymers by aqueous SEC. (C) 2011 Elsevier B.V. All rights reserved

thermosensitive copolymers

Thermosensitive copolymers of N-isopropylacrylamide (NIPA) and N-acryloxysuccinimide (NASI) were obtained by solution polymerization using azobisisobutyronitrile as the initiator in a tetrahydrofuran-toluene mixture at 65degreesC. A boronic acid-carrying ligand, m-aminophenylboronic acid (APBA) was covalently attached to the thermosensitive copolymer via the reaction between amino and succinimide groups. APBA-coupled thermosensitive copolymer exhibited both temperature and pH sensitivity. Thermally reversible phase transitions were observed both in the acidic and alkaline pH region for the APBA-modified copolymers obtained with different NASI feed concentrations. In our study, ribonucleic acid (RNA) was selected as a biomolecule having reactive groups which could potentially interact with the boronic acid functionality. The response of boronic acid-carrying thermosensitive copolymer against RNA was investigated in aqueous media in the pH range 4-9. In the acidic pH region, an increase was observed in the lower critical solution temperature (LCST) of the APBA-coupled thermosensitive copolymer with increasing RNA concentration. However, LCST decreased with increasing RNA concentration at both neutral and alkaline pH values. The LCST of the APBA-attached copolymer varied linearly with the RNA concentration at pH of 3, 4 and 7. (C) 2003 Society of Chemical Industry

A new temperature-sensitive polymer: Poly(ethoxypropylacrylamide)

In this study, a new temperature sensitive polymer was obtained by the solution polymerization of ethoxypropyl-acrylamide. The monomer, N-(3-ethoxypropyl)-acrylamide was synthesized by the nucleophilic substitution reaction of 3-ethoxy-propylamine and acryloyl chloride. The solution polymerization was performed in ethanol at 70 degrees C, by using azobisizobutyronitrile as the initiator. Poly(N-(3-ethoxypropyl)acrylamide), PEPA, exhibited a reversible phase transition by the temperature. The effects of polymer and salt concentrations on the lower critical solution temperature, (LCST) behaviour were investigated. LCST was found to be strongly dependent on the polymer concentration. The dynamic light scattering (DLS) measurements confirmed the formation of aggregates by the association of nucleated polymer chains at the temperatures higher than LCST. However an unusual behaviour, a marked decrease in the hydrodynamic diameter by the increasing PEPA concentration was observed below the LCST. The effect of salt concentration on the critical flocculation temperature of PEPA was reasonably similar to poly(isopropylacrylamide), PNIPA. In the ethanol-water media, the reversible phase transition behaviour was observed up the ethanol concentration of 30% v/v. This study indicated that PEPA was a new alternative thermally reversible material for PNIPA. With respect to the well-defined temperature-sensitive polymers like PNIPA, polymer concentration dependent LCST of PEPA can provide significant advantages in the applications like drug targeting, affinity separation and immobilization of bioactive agents. (c) 2005 Elsevier Ltd. All rights reserved