Reactive Polymers最新文献

Copolymers (I-IV) of 2-acryloylamino-9,16,23-tri(t-butyl)phthalocyanine (APc(t-Bu)₃) and acrylamide derivatives were prepared and their catalytic activity for oxidation of 2-mercaptoethanol was examined. Copolymers (II and IV) of APc(t-Bu)₃ and N-isopropylacrylamide revealed a lower critical solution temperature phenomenon at 29°C in carbonate buffer, that is to say, the copolymers dissolving in buffer solution below 29°C separated out as precipitate above 29°C. The catalytic activity of polymer IV, which was prepared by metalation of copolymer II, markedly changed around 29°C. Copolymer IV served as a homogeneous catalyst of autoxidation of 2-mercaptoethanol below 29°C. In contrast, the catalytic activity drastically decreased above 29°C because of separation as precipitate.

Chelating polymers containing an α-aminobenzylphosphonic acid group or an α-aminopyridylphosphonic acid group have been prepared starting with a crosslinked polyaminomethylstyrene. Chemical modification was achieved via the addition of diethyl phosphonate followed by hydrolysis (Kabachnick-Fields reaction) or by the addition of phosphorous acid onto the corresponding polyimines. Preliminary evaluation of the sorption capacities towards Ca²⁺ and Co²⁺ have shown that the prepared polymers exhibit similar or slightly greater chelating properties than a commercial resin (Duolite ES 467). It was also found that polymers containing an α-aminopyridylphosphonic acid group displayed a significant affinity towards Co²⁺ contrary to resins containing an α-aminobenzylphosphonic acid group.

Six silane-coupling agents having end-branched fluorocarbon chains: (CF₃)₂CF(CF₂)₄CH₂CH₂Si(CH₃)(OCH₃)₂ (1); (CF₃)₂CF(CF₂)₆CH₂CH₂Si(CH₃)(OCH₃)₂ (2); (CF₃)₂CF(CF₂)₈CH₂CH₂Si(CH₃)(OCH₃)₂ (3); (CF₃)₂CF(CF₂)₄CH₂CH₂Si(OCH₃)₃ (4); (CF₃)₂CF(CF₂)₆CH₂CH₂Si(OCH₃)₃ (5); (CF₃)₂CF(CF₂)₈CH₂CH₂Si(OCH₃)₂ (6); were prepared by the hydrosilylation reaction of dichloro(methyl)silane or trichlorosilane with the corresponding end-branched 1H,1H,2H-polyfluoro-1-alkene ((CF₃)₂CF(CF₂)_nCHCH₂, (n = 4, 6 and 8) in the presence of hydrogen hexachloroplatinate(VI), followed by reaction with sodium methoxide. The application for the surface modification of glass was attempted using these compounds. From measurements of the contact angles θ (°) of water and oleic acid against a modified glass surface, it was found that the silane-coupling agents have high modification ability for surface modification. The oxidation resistance of the modified glass surface was also investigated.

Heating of acrylonitrile, vinyl acetate and divinylbenzene porous copolymers (AN-VA-DVB) with aminoguanidine salts in alkaline medium leads to aminolysis and hydrolysis of the nitrile groups and hydrolysis of acetyl groups. As a result, an amphoteric chelating resin with guanidyl and carboxyl groups at a concentration of ca. 13and 2–4 mmol/g, respectively, is obtained. The resin possesses a porous structure with a mean pore radius of 5.6 nm in swollen state. The sorption of Cu(II) ions increases with increasing content of functional groups, and reaches 120–170 mg/g at pH 5. The equilibrium sorption is attained after 300 min. The infrared (IR) spectra of resins confirm that both guanidyl and carboxyl groups form complexes with Cu(II) ions. From analysis of the sorption degree of Cu(II) ions it can be concluded that statistically two groups (carboxyl or/and guanidyl) participate in the complexation. Electron paramagnetic resonance (EPR) spectra of the resins suggest that at low pH the complexes of Cu(II) ions with carboxyl groups dominate. At the pH range 3–8 the formation of Cu(II) complexes with carboxyl and guanidyl groups is evident. At pH > 9 three or four nitrogen atoms participate in coordination sphere around Cu(II).

Chelex 100 chelating resin, as supplied (mixed sodium/hydrogen form 43% /57%), was found to be readily hydrolyzable through hydronium ion exchange from water. Contact with deionized water in solution volume to exchanger weight ratios of 10–4000 brought sodium ions into solution with concentrations of 0.05–1.5 mM and increased the pH from 6.1 to 8.7–10.0. In addition to sodium and hydroxide, the exchanger was found to release chloride and carbonate ions. The two acetate groups vary substantially in their selectivities to hydronium ions, the corrected selectivity coefficients being 1.3 × 10⁹ and 1.4 × 10³, respectively.

Palladium catalysts supported on polymers, such as poly(N-vinyl-2-pyrrolidone) (PVP), polyacrylamide (PAA), modified poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polysulfone (PSF), were used to catalyze the carbonylation of allyl halides to form butenoic acid under mild conditions (40°C, 0.1 MPa). These polymer-supported palladium catalysts exhibit very high activity and stability towards the carbonylation of allyl halides. The turnover frequencies (TOF, mol CO/mol Pd min⁻¹) of PVP-Pd are up to 21 and 40 for the carbonylation of allylchloride and allylbromide, respectively, in two-phase (aqueous NaOH-benzene) medium.

After repeated use, the turnover (mol CO/mol Pd) of phosphinated PPO-Pd in the carbonylation of allylbromide can be up to 30,000. The effects of solvent, phase transfer agent and the functional support group on the activity of these catalysts were investigated.

Iron detoxification of human blood plasma was studied with resins containing desferrioxamine B (DFO) or 3-hydroxy-2-methyl-4(1H)-pyridinone (HMP) as iron(III)-chelating groups. The behaviour of four resins was investigated: DFO-Sepharose, HMP-Sepharose and crosslinked copolymers of 1-(β-acrylamidoethyl)-3-hydroxy-2-methyl-4(1H)-pyridinone (AHMP) with 2-hydroxyethyl methacrylate (HEMA) and of AHMP with N,N-dimethylacrylamide (DMAA). The efficiency of iron detoxification of plasma of the resins was mainly dependent on the affinity of the ligands and the hydrophilicity of the resins. The results of a stability study in phosphate-buffered saline at a physiological pH indicated that AHMP-DMAA was the most stable resin, whereas the Sepharose gels had a relatively lower stability. Experiments with the AHMP-DMAA resin showed that the resin was able to remove iron from plasma with different iron contents, and from plasma poisoned with FeCl₃, iron(III) citrate or transferrin. A rapid removal from free serum iron was observed, whereas iron from transferrin was removed slowly afterwards. Only the overload iron was removed since in all cases the normal serum iron level of ca. 1 ppm was obtained.

The behaviour of supported fluoride ion when treated with gaseous sulphur mustard, (ClCH₂CH₂)₂S, has been studied. Amberlyst A-26 F⁻ was found to have a large capacity for reaction (1.5 mmol S-mustard/g resin), the only observed organic product being divinyl sulphide. Fluoride ion on other support materials showed much lower reaction capacity.

Polymer adsorbents have been prepared by post-polymerization crosslinking of the swollen chloromethylated gel-type and macroreticular copolymers of styrene and divinylbenzene. Their morphology has been studied in the dry state by nitrogen adsorption/desorption method and in the swollen state by inverse steric exclusion chromatography. Their sorption properties were tested for the separation of furfural from aqueous solutions. Obtained data were compared with properties of conventional commercial polymer adsorbents Amberlite XAD-2 and XAD-4. At low concentrations of the sorbate in the surrounding solution the highly microporous post-crosslinked materials are much more efficient adsorbents than the conventional commercial polymers. However, their sorption capacity is restricted by limited pore volume and at higher equilibrium concentrations the high surface area macroporous polymers like Amberlite XAD-4 can be more efficient adsorbents.