Carla Muñoz

Thermal properties and TGA-FTIR studies of polyacrylic and polymethacrylic acid doped with metal clusters

Abstract Polyacrylic (PAA) and polymethacrylic acid (PMAA) doped with metal clusters were prepared by radical polymerization. The colloids were obtained by cocondensation of the metals and acrylic acid at 77 K using several metals such as Au, Ag, Pd, Cu, Bi, Sn, Sb, Ge, Ga, In, Cd and Zn. The presence of the metal clusters avoids the formation of larger molecular weight polymers. A complete study of the thermal degradation between 50 and 550°C has been carried out, and the decomposition temperatures (TD) are obtained from the second derivative. In PAA, the highest TD corresponds to the undoped polymer, 546°C, but in PMMA, the Pd doped polymer increases the TD2 from 467 to 469°C for the lowest molecular weight. In fact, the TD of the highest molecular weight polymer increases 27°C the same as PAA-Ge. FTIR spectroscopy of the gases from TGA indicate that the product has been evolved during the experiment (60 min) with PAA, while the first gas evolved between 20 and 30 min and then from 37 to 45 min for PMMA shows that during the first decomposition mainly MAA is found. During the second decomposition besides the characteristic bands for MAA some alkenes are observed.

Metal ion sorption properties of water-insoluble resins based on sodium styrene sulfonate and different comonomers

A set of water-insoluble resins based on sodium styrene sulfonate and different comonomers were synthesized. The resins poly(mono-2-(methacryloyloxy)ethyl succinate-co-sodium 4-styrene sulfonate) P(MOES-co-SSNa), poly(2-acrylamido glycolic acid-co-sodium 4-styrene sulfonate) P(AGA-co-SSNa), poly(acrylamide-co-sodium 4-styrene sulfonate) P(AAm-co-SSNa), and poly(2-(dimethylamine)ethyl acrylate-co-sodium 4-styrene sulfonate) P(DMAEA-co-SSNa) were synthesized by solution radical polymerization. The metal ion retention properties were studied by batch procedure for Cd(II), Zn(II), Pb(II), and Hg(II). Resins performance was compared with a poly(sodium 4-styrene sulfonate) (PSSNa) resin in order to evaluate the effect of comonomer on sorption properties. The effect of pH, time, temperature, and maximum retention capacity were studied. In addition, sorption experiments were carried out under competitive ion conditions to study the selectivity of resins. The resins P(AAm-co-SSNa) and P(AGA-co-SSNa), showed the most important differences compared with PSSNa resin, the former present higher sorption and the latter presented selectivity for Hg(II) at pH 2.

Poly(N-hydroxymethyl acrylamide-co-acrylic acid) and poly(N-hydroxymethyl acrylamide-co-acrylamidoglycolic acid): synthesis, characterization, and metal ion removal properties

Macroreticular chelating resins containing carboxylic groups, poly(N-hydroxymethyl acrylamide-co-acrylic acid) P(HMA-co-AA) and poly(N-hydroxymethyl acrylamide-co-2-acrylamido glycolic acid) P(HMA-co-AGA) were synthesized by solution radical polymerization with ammonium persulfate as initiator and N,N′-methylene-bis-acrylamide as cross-linking reagent. The polymerization yield was 98.9 and 91.9% for P(HMA-co-AA) and P(HMA-co-AGA), respectively. The retention properties were studied under competitive and noncompetitive conditions by batch equilibrium procedure for the following metal ions: Cd(II), Cr(III), Zn(II), Pb(II), and Hg(II). The effects of pH, time, temperature, and initial ion concentration on adsorption were investigated. The resins showed a significant ability to retain Pb(II), greater than 79%, at pH 5.

Poly(4-sodium styrene sulfonate-co-4-acryloylmorpholine). Synthesis, Characterization, and Metal Ion Retention Properties

Abstract A novel resin poly(sodium 4-styrene sulfonate-co-4-acryloyl morpholine) was synthesized through a radical solution polymerization in solution and studied as an adsorbent under uncompetitive and competitive conditions by batch and column equilibrium procedures for the following divalent metal ions Cd(II), Zn(II), Pb(II), and Hg(II), and trivalent Cr(III). For all metal ions, the adsorption was strongly influenced by the pH. The maximum retention capacity, 3.29 mmol of metal ion/g, was obtained for Zn(II) at pH 5 by batch equilibrium procedure. For both the batch and column procedures, the retention behavior was similar for Cd(II), Cr(III), Zn(II), and Pb(II).

Interactions of Water‐Soluble Poly(sodium 4‐styrenesulfonate) with Iminodiacetic Acid and Cu2+

The multicomponent system consisting of poly(sodium 4-styrenesulfonate) (PSS), iminodiacetic acid (IDAA), and Cu(NO3)2 in water at pH 4 was studied by means of ultrafiltration at low and relatively high ionic strengths. Under the experimental conditions, IDAA is negatively charged, and is slightly retained in ultrafiltration experiments in the presence of the water-soluble polyelectrolyte PSS. The positively charged copper ions are strongly retained by PSS. Due to the capability of IDAA to form stable complexes with Cu2+ ions, the resulting blue 1:1 complex between IDAA and Cu2+ is not retained by PSS, but is eluted from the ultrafiltration cell at pH 4.