Poly Hydroxamic Acid Research Articles

In vitro dynamic swelling behaviors of polyhydroxamic acid hydrogels in the simulated physiological body fluids

Influence of some simulated physiological body fluids on the dynamic swelling behaviour of polyelectrolytic hydroxamic acid hydrogels (PHA) was investigated at 37 °C in vitro. The simulated physiological body fluids are distilled water, human sera, physiological saline (0.89 % NaCl), isoosmotic phosphate buffer at pH 7.4, gastric fluid at pH 1. 1, (gylicine-HCl buffer), urea (0.3 mol L−1), and the aquatic solutions of K2HPO4 and KNO3 (the sources of K+). The values of equilibrium swelling of PHA hydrogels varied in the range of 130–4625%, while the values of equilibrium fluid content of the hydrogels varied in the range of 57–97%. The initial rate of swelling, diffusional exponent, and, diffusion coefficient were calculated using swelling kinetics data. Diffusion of the fluids into the hydrogel was found to be non-Fickian character. The diffusion coefficients of the hydrogel varied between 0.6×10−6– 8.1×10−6 cm2 s−1.

The use of positron annihilation lifetime technique to study the effect of doping metal salts on polyhydroxamic acid polymers

Polyhydroxamic acid (PHA) from polymethacrylamide (PMAA) was prepared. Chromium chloride (CrCl3) and ferric chloride (FeCl3) salts were added to the polymer in order to increase its electrical conductivity, i.e., the dopants help produce semiconducting properties. The positron annihilation lifetime technique spectroscopy (PALS) was used to study the changes in the free volume as a function of FeCl3 and CrCl3 concentrations. ortho-Positronium lifetime components were used to estimate the free volume parameters. It was found that the hole size and the total free volume fraction decreased with FeCl3 concentration. On the other hand, the hole size increased slightly with CrCl3 concentration and then decreased, while the total free volume fraction increased continuously. The free volume distributions were determined from ortho-positronium distributions. The electric conductivity as a function of FeCl3 and CrCl3 concentrations showed fluctuation behavior and showed a continuous increase with the increase in temperature. The correlation between positron annihilation parameters and electric conductivity were discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2095–2101, 2001

Polyhydroxamic Acids for the Chromatographic Separation of Metal Ions

Polyhydroxamic Acids for the Chromatographic Separation of Metal Ions

Synthesis and characterization of highly porous poly(methacrylic-co-triethylene glycol dimethacrylate) by suspension polymerization

Porous poly(methacrylic-co-triethyleneglycol dimethacrylate) (MAA-3G) was prepared by suspension polymerization using benzoyl peroxide as an initiator, poly(vinyl alcohol) as a protective colloid, and n-hexane as a porogenic agent. The prepared polymer was base hydrolysed using hydroxyl amine and sodium methoxide into the corresponding polyhydroxamic acid (HYOX). The metal binding behavior of polyhydroxamic acid with various metal ions, the effect of pH on the metal ion capturing, and the selectivity of the resin towards the different metal ions were also examined by means of atomic absorption spectrophotometer. The thermal stability of the prepared base-hydrolysed polymer and the metal polymer complex was examined by thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC). The prepared porous polymer methacrylic-co-triethyleneglycol dimethacrylate and its different modulated forms were characterized by means of FTIR specroscopy and scanning electron microscope. The hydroxamic acid content was also examined by elemental analysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 149–159, 1999

Comparison Between the Electric Conductivity of Polyhydroxamic Acids of Different Origin

Polyhydroxamic acid (PHA) was prepared from polyacrylamide (PAA) and from polymethacrylamide (PMAA). It was found that PHA from PAA has the properties of a semiconductor when it reacts with some metals. PHA from PMAA has typical semiconducting properties when reacting with 1 mmol of ferric chloride, whereas its electric conductivity is somewhat lower when it contains 0.5 mmol of ferric chloride.

Polyhydroxamic acids: synthesis, ion exchange separation and atomic absorption spectrophotometric determination of divalent metal ions

The preparation and properties of 8 N-phenylsubstituted polyacrylohydroxamic acids as ion exchange resins are described. These were synthesized by the reaction of polyacryloyl chloride with N-aryl hydroxylamines in etherial medium. The chelating properties of the resins were determined and compared with each other. The extraction of divalent metal ions as a function of pH and kinetics of their sorption were studied. The chromatographic separation of metal ions from the mixtures is also described.

Convenient method for the preparation of some polyhydroxamic acids: Michael addition of amines to acrylohydroxamic acid derivatives

Reagents 1, 2, and 3 are readily prepared by the reaction of the appropriate hydroxylamine derivatives with acryloyl chloride. They undergo Michael addition with a variety of amines to give the corresponding O-protected hydroxamate derivatives in moderate to good yields. Subsequent removal of the protecting group provides a convenient method for the preparation of a number of mono, di, tri and tetrahydroxamic acids.

Chelating ion-exchangers containing n-substituted hydroxylamine functional groups: Part 6. Sorption and separation of gold and silver by a polyhydroxamic acid

The sorption and desorption characteristics of gold and silver on a polyhydroxamic acid chelating resin are described. Gold is quantitatively sorbed from 0.5 M nitric acid or neutral solutions, and readily eluted with 0.5% ( w v ) potassium cyanide solution. Silver is removed from 0.05 M nitric acid or neutral solutions, and can be eluted with the cyanide solution or with 0.5 M nitric acid. Gold can be quantitatively separated from copper, iron and silver; gold and silver are sorbed from dilute cyanide solutions. Tests with river water and other eluting systems are reported.

Desferrioxamine

Desferrioxamine B is the iron-free derivative of an iron-containing polyhydroxamic acid isolated from cultures of streptomyces pilosus. Desferal (Ciba), its water-soluble methane sulphonate, will soon be marketed in this country. Desferrioxamine B has a greater affinity for iron than transferrin, the iron-binding globulin of plasma, while its affinity for calcium, magnesium and other metals is less than that of chelating EDTA derivatives.