Abstract:The definite polymers containing 1,4‐dihydronicotinamide structure were prepared by reduction with sodium dithionite‐potassium carbonate in the presence of benzyltriethylammonium chloride. The reduction of vicinal tricarbonyl compounds such as alloxan and ninhydrin by polymers having the 1,4‐dihydronicotinamide moiety was performed to isolate the polymers' trapped radical anion of alloxan or ninhydrin.
“…However, the homopolymer could be reversibly dissolved and precipitated when the aqueous solution contained NaCl. In the absence of NaCl, the PCVPC polymer formed an insoluble complex between the anioic adduct and the unreacted cationic polymer at the midway point of the reduction reaction. , Avoidance of this complex formation at high ionic strengths can make the polymer easily oxidizable, so that polyelectrolyte chains are regenerated. 3 Transmittance of aqueous solutions containing CVPC homopolymer at 750 nm. Ionic strength ( I ) was adjusted with NaCl: (□) I = 0; (○) I = 0.1; (·) I = 1.0.…”
Section: Resultsmentioning
confidence: 99%
“…In the absence of NaCl, the PCVPC polymer formed an insoluble complex between the anioic adduct and the unreacted cationic polymer at the midway point of the reduction reaction. 19,20 Avoidance of this complex formation at high ionic strengths can make the polymer easily oxidizable, so that polyelectrolyte chains are regenerated.…”
An oxidoreduction-sensitive polymer, poly [3-carbamoyl-1-(p-vinylbenzyl)pyridinum chloride] (PCVPC), was grafted on a porous membrane, and the water permeation through the membrane was investigated. PCVPC homopolymer was found to be water soluble in the oxidized state but insoluble in the reduced state. It could be reversibly dissolved and precipitated in aqueous solutions of high ionic strengths. The polymer was grafted onto a glow-discharged fluoropolymer membrane. In the oxidized state the grafted chains were ionized and extended to cover the pores and decrease water permeation. The rate of permeation depended significantly upon the ionic strength of the aqueous solution. In the reduced state, however, the polymer brushes were deionized and increased water permeation. These changes in permeability were reversible by oxidoreduction, when the formation of an insoluble polymer complex in the reduction process was avoided under high ionic strength. The response of polymer chains grafted on the membrane corresponded to that of polymers in solution.
“…However, the homopolymer could be reversibly dissolved and precipitated when the aqueous solution contained NaCl. In the absence of NaCl, the PCVPC polymer formed an insoluble complex between the anioic adduct and the unreacted cationic polymer at the midway point of the reduction reaction. , Avoidance of this complex formation at high ionic strengths can make the polymer easily oxidizable, so that polyelectrolyte chains are regenerated. 3 Transmittance of aqueous solutions containing CVPC homopolymer at 750 nm. Ionic strength ( I ) was adjusted with NaCl: (□) I = 0; (○) I = 0.1; (·) I = 1.0.…”
Section: Resultsmentioning
confidence: 99%
“…In the absence of NaCl, the PCVPC polymer formed an insoluble complex between the anioic adduct and the unreacted cationic polymer at the midway point of the reduction reaction. 19,20 Avoidance of this complex formation at high ionic strengths can make the polymer easily oxidizable, so that polyelectrolyte chains are regenerated.…”
An oxidoreduction-sensitive polymer, poly [3-carbamoyl-1-(p-vinylbenzyl)pyridinum chloride] (PCVPC), was grafted on a porous membrane, and the water permeation through the membrane was investigated. PCVPC homopolymer was found to be water soluble in the oxidized state but insoluble in the reduced state. It could be reversibly dissolved and precipitated in aqueous solutions of high ionic strengths. The polymer was grafted onto a glow-discharged fluoropolymer membrane. In the oxidized state the grafted chains were ionized and extended to cover the pores and decrease water permeation. The rate of permeation depended significantly upon the ionic strength of the aqueous solution. In the reduced state, however, the polymer brushes were deionized and increased water permeation. These changes in permeability were reversible by oxidoreduction, when the formation of an insoluble polymer complex in the reduction process was avoided under high ionic strength. The response of polymer chains grafted on the membrane corresponded to that of polymers in solution.
“…Synthesis and Purification of Monomers. 3-Carbamoyl-l-(p-vinylbenzyl)pyridinium chloride was synthesized as reported previously (9). p-(Chloromethyl)styrene (11.9 g, 78.2 mmol) and nicotinamide (15 g, 123 mmol) were mixed in N^ZV-dimethylformamide (250 mL) and the solution was stirred for 24 h at 4 °C.…”
Trypsin was modified with various vinyl polymers by the graft polymerization of vinyl monomers using a trypsin derivative containing aliphatic azo groups as the initiator. The graft polymers were chosen to be sensitive to external signals, e.g., a redox-sensitive poly[3-carbamoyl-1-(p-vinylbenzyl)pyridinium chloride] and a pH-sensitive poly(methacrylic acid-co-methyl methacrylate). The trypsin modified with the redox-sensitive polymer became insoluble in water in the presence of Na2S2O4, and redissolved when H2O2 was added. However, the enzymatic activity of the homogeneous solution was not proportional to the concentration of the modified trypsin remaining in the solution. The trypsin modified with the pH-sensitive polymer was insoluble and soluble in acidic and neutral solutions, respectively. The enzymatic activity of the homogeneous solution changed reversibly with pH in proportion to the concentration of the modified trypsin remaining in the solution.
“…However, the precipitated PCVPC was not solubilized upon addition of an aqueous oxidant solution in the absence of added salt. In the absence of NaCl, the PCVPC should form an insoluble complex between the anionic adduct and the unreacted cationic polymer in the middle of the reduction reaction [43,44]. Figure 12 shows how the rate of water permeation changes by alternative additions of oxidant and reductant.…”
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