Reactive and Functional Polymers (v.52, #1)

In this study, hydrogels having a thermoresponsive character were prepared from the ternary systems N-isopropylacrylamide/acrylamide/2-hydroxyethyl methacrylate by a redox copolymerization method. Hydrogels with different thermoresponsive properties were obtained by changing the initial NIPAM/AAm and NIPAM/HEMA mole ratios and total monomer concentration.
Keywords: N-isopropylacrylamide; Acrylamide; 2-Hydroxyethyl methacrylate; Thermoresponsive polymer;

Poly(styrene-co-acryloyl chloride) prepared from poly(styrene-co-p-nitrophenylacrylate), crosslinked with divinylbenzene, readily reacted with N, O, S and C nucleophiles resulting in amido, hydrazido, ester, thioester and malononitryl derivatives of poly(styrene-co-acryloyl chloride). All the introduced reagents (1-propanol, 3-methyl-1-butanol, thiophenol, 3-fluoroaniline, 4-chloroaniline, 3,4-dichloroaniline, 2-aminobenzimidazole, phenylhydrazine and malononitrile) reacted under mild conditions (room temperature). No additional crosslinking was observed during processes with hydrazine or amines. Scavenging abilities of crosslinked poly(styrene-co-acryloyl chloride) and crosslinked poly(styrene-co-acrylic acid) were demonstrated by scavenging benzylamine, which was removed from the solution at room temperature, reaction being faster with supported acid chloride.
Keywords: Poly(styrene-co-p-nitrophenylacrylate); Poly(styrene-co-acryloyl chloride); Polymer supports; Polymer supported quenching; Scavenger resins;

The syntheses of three isomeric, wholly aromatic polyketones composed of a trifluoromethylated biphenylene unit and a 2,2′-dimethoxybiphenylene unit were performed via direct electrophilic aromatic acylation polycondensation of finely designed monomers. The two isomers of sequentially controlled wholly aromatic polyketones, i.e. the head-to-tail and head-to-head isomers, composed of 2-trifluoromethyl-4,4′-biphenylene and 2,2′-dimethoxy-5,5′-biphenylene units were synthesized successfully. Furthermore, treatment of 2-trifluoromethylbiphenylene-4,4′-dicarboxylic acid and 2,2′-dimethoxybiphenyl with P2O5–MsOH gave another isomeric polyketone having a random sequence.
Keywords: Aromatic polyketones; Fluorine-bearing polymers; Sequentially controlled polymers; Direct condensation;

A polyacrylamide–polyacrylic acid copolymer hydrogel was prepared by the controlled hydrolysis of polyacrylamide in an alkaline solution of 10% sodium hydroxide. The structure and composition of the resulting copolymer hydrogel was approximately two acrylic acid units for every acrylamide unit. The capacity of the copolymer hydrogel to bind various metal ions was tested under a range of uptake conditions, with varying uptake time, pH and ionic strength. Ions such as Cu2+ and Cd2+ were bound more strongly to the copolymer hydrogel than the competing ions of Na+, K+, Ca2+ and Mg2+, particularly at pH>5, largely due to the increased acidity of these transition metal ions. Metals bound to the copolymer hydrogel were efficiently (>94%) eluted in 2 M HNO3 solution. The copolymer was found to have a pK a of ∼4.5 and had an equilibrium swelling ratio of 120 at pH>6 with an ionic strength equivalent to 0.01 M NaCl, and a swelling ratio of 265 at low ionic strengths. This material should be of use for the recovery and separation of Cu2+ and Cd2+ ions, and trace environmental analysis applications such as the diffusive gradients in thin films (DGT) technique.
Keywords: Polyacrylamide–polyacrylic acid copolymer; Trace metal binding; Copper; Cadmium; Diffusive gradients in thin films (DGT); Swelling;

In order to find an effective and reliable method for separating mixed ion-exchange resins, the flotation method was tested with the aid of a surfactant. Cationic surfactants selectively bound acidic resins in the presence of basic resins, while anionic surfactants were preferentially bound on basic resins rather than acidic resins. Only the surfactant-adsorbed resins floated in aqueous solution, so that easy separation and recovery of mixed resins could be achieved. Surfactant adsorption was examined by elemental analysis and surfactant titration, and the recovered resins were identified by SEM. Finally, the flotation method was applied to the sensing of surfactants in aqueous solution.
Keywords: Ion exchange; Resin; Flotation; Surfactant; Ion-sensing;

Synthesis and some sorption properties of the anion-exchangers with biguanidyl groups by Bożena N Kolarz; Andrzej W Trochimczuk; Dorota Jermakowicz-Bartkowiak; Julia Jezierska; Wiesław Apostoluk (53-60).
In this work, a method of synthesis of the resins bearing biguanidyl groups is presented. It includes exchange of chlorine in the terpolymer of styrene–vinylbenzyl chloride and 2 wt.% of divinylbenzene for ethylenediamine and the reaction of the amino groups with sodium dicyanamide. Thus obtained groups were converted to biguanidyl ones with urotropine. Resins are displaying sufficiently high biguanidyl ligand content, 1.7 mmol/g. The presence of guanidyl and biguanidyl groups does not improve sorption of Cu(II), which is due only to the nitrogens originating in ethylenediamine, as indicated by the electron paramagnetic resonance (EPR) spectra. Obtained resins have negligible sorption of Ni(II) and Co(II) but they have high capacity towards dicyanoaurate anions and gold chlorocomplexes. The sorption of gold from diluted 2 ppm solution of dicyanoaurate reaches 19 mg of Au/g of dry resin.
Keywords: Gold sorption; Anion-exchanger; Biguanidyl resin; Copper(II) sorption; EPR copper(II) complexes;