Groups Of PAA Research Articles

Precursor Polymer Effect on Polyimide/Silica Hybrid Nanocomposite Films

Here we report the influence of the polyimide precursor type on the surface morphology and properties of poly(p-phenylene biphenyltetracarboximide) (BPDA-PDA PI)/silica hybrid composite films. Two types of precursor polymer were employed: poly(p-phenylene biphenyltetracarboxamic acid) (BPDA-PDA PAA) and poly(p-phenylene biphenyltetracarboxamic diethyl ester) (BPDA-PDA PES). These precursor polymers were mixed with tetraethoxysilane in the presence of HCl and H2O, which led to the precursor mixture films that contain in-situ generated silica particles via sol-gel process. Then the precursor mixture films were subject to thermal imidization to make polyimide/silica hybrid composite films. Results showed that the PAA precursor has better compatibility with silica particles, which is mainly attributed to the early making of silyl ester bonds (as evidenced by X-ray photoelectron spectroscopy) between carboxylic acid groups in the PAA and hydroxyl groups in silanol molecules. Further evidences were provided by the measurement of surface nanomorphology, crystal nanostructure, thermal/mechanical properties, and optical birefringence.

Adsorption of metal cations from aqueous solutions onto the pH responsive poly(vinylidene fluoride grafted poly(acrylic acid) (PVDF-PAA) membrane

This study investigated the influence of pH of adsorption medium and co-adsorptive metal cations for the adsorption of potassium (K+) and magnesium (Mg2+) ions onto poly (vinylidene fluoride) grafted poly(acrylic acid) (PAA-PVDF) membrane. At pH 4.8, the adsorption of potassium and magnesium was minimal, because of nearly non-dissociated carboxylic acid groups of PAA-chains, but adsorption increased with increasing ion concentration. The interaction of the studied cations between PVDF-PAA membranes increased considerably at pH 7.0 the dissociation of carboxylic acid groups of PAA. The addition of ionic substances (calcium (Ca2+) and sodium (Na+) to the adsorption medium reduced the adsorption of potassium and magnesium onto the membrane, because of co-adsorption. Divalent calcium reduced more effectively than univalent sodium the adsorption of potassium and magnesium onto the membrane. In conclusion, co-adsorbing ions reduced the adsorbed amount of potassium and magnesium ions due to binding competition. The percentual adsorbed values suggest that adsorption affinity of studied ions onto the PVDF-PAA membrane followed the order Na+ < K+ < Mg2+ < Ca2+. The effect of metal cations on drug adsorption from biological fluids needs research in the future, because e.g. PVDF-PAA membrane has been used in drug separation processes.

Study of polymer–metal ion–membrane interactions in liquid-phase polymer-based retention (LPR) by continuous diafiltration

In this work were studied polymer–metal ion–membrane interactions during continuous diafiltration of divalent metal ions (Co 2+, Ni 2+, Cu 2+, Zn 2+, Cd 2+, and Pb 2+) using poly(acrylic acid) (PAA) as water soluble polymer by liquid-phase polymer-based retention (LPR) technique at pH 6. Polyethersulfone (PES) membranes were used and characterized by different methods (solute rejection test, force atomic microscopy (AFM) and contact angle). Changes on fouled membrane roughness (22.91 ± 2.2) with respect to virgin membrane (7.05 ± 4.6) and changes on contact angle measures (76.0 ± 0.9 and 85.0 ± 2.34 with water) suggest an increasing in surface hydrophobicity of PES membrane associated mainly with deposited forming on the surface as results of enhanced in the polymer–membrane interaction throughout proceed filtration. From metal ion concentration data in the permeate throughout filtration experiment polymer–metal interactions were studied and analyzed by equations based on the combination of molar binding ratio and the consideration of chemical equilibrium between the polymer and metal ions. Membrane–metal ion interaction was around 10% for all cations studied, with the following order in the interactions: Ni 2+ ≈ Zn 2+ > Pb 2+ > Co 2+ > Cu 2+ > Cd 2+. A relatively high and specific interaction of the carboxylate groups of PAA with metal ions was observed. This interaction showed the order: Cu 2+ > Cd 2+ > Co 2+ > Ni 2+ ≈ Zn 2+.

Structure-effect relationship in the down-regulation of glutaminase in cultured human cells by phenylarsenic compounds

Diphenylarsinic acid [DPAA(V)] was detected in ground water used as drinking water after a poisonous incident in Kamisu, Japan. An approach to define the target molecules of DPAA(V) with a high throughput analysis of proteins from cultured human cells demonstrated down-regulation of glutaminase C (GAC). GAC is a splicing variant of the kidney-type glutaminase (KGA) gene and has the enzyme activity of phosphate-activated glutaminase (PAG). To gain some insights into the mechanism of arsenic intoxication in Kamisu, the effects of various arsenic compounds, including arsenicals that were detected in ground water ([DPAA(V)], phenylarsonic acid [PAA(V)] and bis(diphenylarsine)oxide [BDPAO(III)]) and rice (phenylmethylarsinic acid [PMAA(V)]), were investigated for the expression of GAC and PAG activity. When cultured human HepG2 cells were incubated with arsenicals for 24 h, the pentavalent phenylarsenic form of PAA(V) and PMAA(V) as well as DPAA(V) suppressed the expression of GAC protein and PAG activity in a concentration-dependent manner. On the other hand, the trivalent phenylarsenic form of BDPAO(III) had no suppressive effect on GAC and PAG. In addition, trivalent phenylarsenic compounds, such as the glutathione (GSH) conjugate of DPAA(V) [DPA-GS (III)] and triphenylarsine [TPA(III)], and the inorganic arsenics, iAs(V) and iAs(III), and methylated metabolites of inorganic arsenics, dimethylarsinic acid [DMA(V)] and dimethylarsinous acid [DMA(III)], had no suppressive effect on glutaminase. Likewise, methyl substituents of the hydroxyl groups of DPAA(V), PAA(V) and PMAA(V), diphenylmethylarsine oxide [DPMAO(V)] and phenyldimethylarsine oxide [PDMAO(V)], did not have any suppressive effects. These results suggest that pentavalent arsenic compounds with both phenyl groups and hydroxyl groups are effective in the suppression of glutaminase. In addition, the fact that it was only the arsenicals detected in Kamisu that were effective in suppressing glutaminase provides insights into the cause of the arsenic intoxication at Kamisu.

Surface attached-poly(acrylic acid) network as nanoreactor to in-situ synthesize palladium nanoparticles for H 2O 2 sensing

A novel amperometric sensor for hydrogen peroxide (H 2O 2) was developed based on palladium nanoparticles (NPs) in-situ formed on the electrode surface. Poly(acrylic acid) (PAA) was first electrodeposited onto a gold electrode. Then Pd 2+ were chemically adsorbed within the PAA network, and subsequently reduced by hydrazine hydrate to form palladium NPs. The size and density of palladium NPs can be easily controlled through controlling the amount of metal ions in the film. The PAA-templated Pd NPs displayed excellent electrocatalytical response to the reduction of H 2O 2. Under optimal conditions, linear relationship was observed for H 2O 2 reduction in the concentration range from 10 μM to 25 mM at the applied potential of −0.1 V and the detection limit was 5 μM. The resulted sensor shows fast response and good stability. By varying the metal catalyst and by conjugating biomolecules with the free carboxyl groups of PAA, a variety of new chemical and biosensors could be constructed.

A novel two‐component physical gel based on interaction between poly(acrylic acid) and 6‐deoxy‐6‐amino‐β‐cyclodextrin

AbstractA two‐component physical organogel was produced by interactions of 6‐deoxy‐6‐amino‐β‐cyclodextrin (β‐CDNH2) and poly(acrylic acid). The microstructure and morphology of the gels were characterized by scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy. It was revealed that the intermolecular hydrogen bonds between the molecules of β‐CDNH2 and the electrostatic interaction between the carboxyl groups of PAA and amino group of β‐CDNH2 were the main driving forces for the formation and maintenance of the network structures of the gel. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers

Synthesis of Hydroxypropylcellulose-poly(acrylic acid) Particles with Semi-Interpenetrating Polymer Network Structure

To develop a novel type of semi-IPN particles using biocompatible materials, hydroxypropylcellulose-poly(acrylic acid) (HPC-PAA) particles with semi-interpenetrating polymer network structure and a porosity-structural surface were prepared by direct polymerization of acrylic acid monomer in the reaction system comprised of HPC and AA monomer and N,N'-methylenebisacrylamide (MBAAm). The properties of HPC-PAA gel particles were characterized by dynamic light scattering, FT-IR, transmission electron microscopy, and atomic force microscope. It is found that the formation of HPC-PAA gel particles is driven by the hydrogen bonding interaction between proton-donating PAA and proton-accepting HPC. These HPC-PAA gel particles exhibit thermo and pH dual-responsive behaviors. Depending on the chemical composition and the degree of cross-linking, the thermo-responsive property of HPC-PAA gel particles can be shifted from the UCST to the LCST property, and particle sizes can be changed from 100 to 1 microm in a controllable way. Successful loading of the gel particles with oxaliplatin, a hydrophilic antitumor drug, was achieved by take advantage of the complex interaction between the platinum atom of oxaliplatin and the carboxylic group of PAA in the gel particles. In vitro cytotoxicity assay indicates that the oxalipatin-loaded HPC-PAA gel particles have high anticancer activity. Considering the good biosafety, simple and mild preparation strategy and tunable size as well as the stimuli-responsive properties, the HPC-PAA gel particles should be a promising candidate for the drug delivery system.

Thermal degradation of [poly( N-vinylimidazole)–polyacrylic acid] interpolymer complexes

Interpolymer complexes of a slightly basic polymer, poly( N-vinylimidazole) (PVIm) with a strongly acidic polymer, poly(acrylic acid) (PAA) have been prepared by mixing aqueous solutions of the respective components. Spectroscopy and thermal methods were used to reveal interaction between VIm and AA moieties. FT-IR analysis showed that the nitrogen atoms at 3rd position of imidazole ring are involved in strong H-bonding with acid groups of PAA leading to a uniform and fully miscible complex structure. As the quantity of PAA increases the thermal stability of complex increases based on TG results. In the DSC analyses, the single T g for all IPC samples showed that IPCs have good or definite miscibility over the whole range of composition as a result of H-bond formation between acrylic acid and imidazole units.

Hydrophilicity-controllable Microporous Hybrid Materials by Anion Exchange

Abstract Poly(acrylic acid) (PAA)/silica hybrids having imidazolium chloride [IL(Cl−)] moieties could be prepared by utilizing ionic interactions between anionic carboxylic acid groups of PAA and cationic imidazolium groups of silica phase. By removing PAA from the obtained hybrids, we could obtain hydrophilicity-controllable microporous hybrids by means of anion-exchange reaction of imidazolium moieties.

State of the Dispersant and Particle Surface During Wet‐Jet Milling for Preparation of a Stable Slurry

Wet‐jet‐milled alumina slurries exhibited distinctly different stability behavior compared with ball‐milled ones in terms of reflocculent efficiency and rheological properties. The distinction was attributed to the different behavior of the same dispersant (NH4+ salt of poly(acrylic acid); PAA–NH4+) in ball milling and wet‐jet milling. Alumina particles after the wet‐jet milling retained the initial surface conditions, although ball‐milled alumina particles yielded more hydroxyl groups on the surface. Furthermore, degradation of dispersant on milling was investigated qualitatively. Infra‐red analysis and isoelectric point measurements suggested that degradation of the dispersant occurred during ball milling, indicating neutralization of the dispersant due to formation of monodentate COOX groups. On the other hand, in the case of wet‐jet milling, COO− groups of PAA–NH4+ were not degraded at all, indicating maintenance of the structures of dispersant with electrostatic repulsion. Change in the polymer size of the dispersant by different milling methods was confirmed using high performance liquid chromatography (HPLC) measurements. The HPLC results of the wet‐jet milled samples showed that a dispersant with a larger molecular size was generated. Force measurement on approach via the colloid probe method in the centrifuged supernatant of the milled slurries confirmed that the interaction distance between an α‐alumina colloid probe and c‐sapphire surface was about two times larger in the wet‐jet‐milled slurry supernatant compared with the ball milled one. Thus, it was found that wet‐jet milling process led to a stable slurry because of the maintenance of not only steric repulsion but also electrostatic repulsion.

Application of Fourier transform infrared spectroscopy to study the interactions of poly(acrylic acid) and mixtures of poly(acrylic acid) and polyacrylamide with bone powders and hydroxyapatites

Fourier transform infrared (FTIR) spectroscopy was used to study the interactions of aqueous solutions of poly(acrylic acid) (PAA) and mixtures of aqueous solutions of PAA and polyacrylamide (PAAm) with chemically and thermally treated bone powders (BPs) and two commercial hydroxyapatites (HAs). An analysis of the spectra of the precipitates that resulted from the mixtures of PAA and the chemically treated samples of BP revealed that the spectra exhibited three new bands at 1544, 1552, and 1661 cm−1. The first band was attributed to the formation of calcium–polycarboxylate resulting from the interaction between the carboxylic acid groups of PAA and the calcium ions of BP. The appearance of the other two bands, in addition to the disappearance of the band corresponding to the absorption of the acid groups of PAA, provided strong evidence for the existence of other interactions between the carboxylic acid groups and the amide groups of the organic matrix of BP. On the other hand, the FTIR spectra of the samples that resulted from the mixture of PAA and thermally treated BP and the two commercial HAs showed only a new absorption band at 1544 cm−1. The interactions of mixtures of the aqueous solutions of PAA and PAAm, adjusted at low or high pH values, with the different BPs and HAs were examined. The mixtures of the aqueous solutions of PAA and PAAm interacted with the different BPs and two HAs, resulting in the formation of ternary PAA–BP–PAAm and PAA–HA–PAAm complexes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

The efficacy of acrylic acid grafting and arginine–glycine–aspartic acid peptide immobilization on fibrovascular ingrowth into porous polyethylene implants in rabbits

To determine the effects of acrylic acid (AA) grafting by argon plasma treatment and of immobilization of arginine-glycine-aspartic acid (RGD) peptides on fibrovascular ingrowth rate into high-density porous polyethylene (HPPE) anophthalmic orbital implants. Sixty rabbits were divided into three groups, with 20 rabbits in each group: (1) control group, rabbits implanted with unmodified HPPE; (2) PAA group, rabbits implanted with HPPE grafted with poly(AA) by argon plasma treatment; (3) RGD group, rabbits implanted with HPPE grafted with AA by argon plasma treatment and subsequently immobilized with RGD peptide. An HPPE spherical implant was put in the abdominal muscles of rabbit. After implantation for 4 weeks, the retrieved implants were sectioned and stained with hematoxylin and eosin (H&E). Blood vessels were counted using CD-31 immunostaining. Cross-sectional areas of fibrovascular ingrowth, blood vessel densities, and host inflammatory response scores were determined for all three groups. The mean cross-sectional areas of fibrovascularization at 2 and 3 weeks after implantation were the greatest in the RGD group, followed by the PAA group. While minimal fibrovascular ingrowths were noted in all implants at 1 week, all the implants showed nearly complete ingrowth at 4 weeks. Blood vessel densities were the highest in the RGD group, followed by the PAA group at 2, 3, and 4 weeks. The mean inflammation scores of the PAA and RGD groups were less than that of the control group. Fibrovascularization into HPPE implants was enhanced by surface grafting of AA and further improved by immobilizing RGD peptides onto the grafted AA surfaces. The inflammatory reactions were mild by either technique of surface modification.

Controlling the Aggregation of Conjugates of Streptavidin with Smart Block Copolymers Prepared via the RAFT Copolymerization Technique

Block copolymers containing stimuli-responsive segments provide important new opportunities for controlling the activity and aggregation properties of protein-polymer conjugates. We have prepared a RAFT block copolymer of a biotin-terminated poly(N-isopropylacrylamide) (PNIPAAm)-b-poly(acrylic acid) (PAA). The number-average molecular weight (M(n)) of the (PNIPAAm)-b-(PAA) copolymer was determined to be 17.4 kDa (M(w)/M(n) = 1.09). The PNIPAAm block had an M(n) of 9.5 kDa and the poly(acrylic acid) (PAA) block had an M(n) of 7.9 kDa. We conjugated this block copolymer to streptavidin (SA) via the terminal biotin on the PNIPAAm block. We found that the usual aggregation and phase separation of PNIPAAm-SA conjugates that follow the thermally induced collapse and dehydration of PNIPAAm (the lower critical solution temperature (LCST) of PNIPAAm is 32 degrees C in water) is prevented through the shielding action of the PAA block. In addition, we show that the cloud point and aggregation properties (as measured by loss in light transmission) of the [(PNIPAAm)-b-(PAA)]-SA conjugate also depended on pH. At pH 7.0 and at temperatures above the LCST, the block copolymer alone was found to form particles of ca. 60 nm in diameter, while the bioconjugate exhibited very little aggregation. At pH 5.5 and 20 degrees C, the copolymer alone was found to form large aggregates (ca. 218 nm), presumably driven by hydrogen bonding between the -COOH groups of PAA with other -COOH groups and also with the -CONH- groups of PNIPAAm. In comparison, the conjugate formed much smaller particles (ca. 27 nm) at these conditions. At pH 4.0, however, large particles were formed from the conjugate both above and below the LCST (ca. 700 and 540 nm, respectively). These results demonstrate that the aggregation properties of the block copolymer-SA conjugate are very different from those of the free block copolymer, and that the outer-oriented hydrophilic block of PAA shields the intermolecular aggregation of the block copolymer-SA bioconjugate at pH values where the -COOH groups of PAA are significantly ionized.

Influence of polyelectrolyte dispersants on the surface chemical properties of aluminum in aqueous suspension

Colloidal processing is widely used for forming ceramics. However, its application to metal was rarely reported. To apply colloidal processing to form IrAl intermetallic compound, detailed knowledge about the surface properties of Al and its interaction with the solvent and dispersants is indispensable. In this study, the hydration process, the surface potential and particle dispersion of Al in aqueous suspension with and without dispersants were investigated. The effects of two polyelectrolyte dispersants, an anionic PAA − and a cationic PEI-H +, were studied. Time dependence of pH value indicated that both dispersants promoted the hydration of Al, while the slow hydration stopped in several hours due to the formation of the bayerite layer. Addition of the dispersants greatly increased the absolute zeta potential values, indicating strong interactions with the Al particle. Comparison of particle size suggested that PEI-H + was better than PAA − for the dispersion of Al, although the latter could induce a much higher absolute zeta potential. FTIR spectroscopy indicated that the interaction in the Al–PAA − system was mainly between the –COO − group of PAA − with the Al surface groups, while hydrogen bonding was the main interaction in the Al–PEI-H + system. The results also implied that not the electrostatic effect, but the steric effect was dominant for the dispersion of Al.

Preparation, characterization and dielectric properties of 4,4-diphenylmethane diisocyanate (MDI) based cross-linked polyimide films

Four different types of cross-linked polyimides based on 4,4-diphenylmethane diisocyanate (MDI) were prepared by the reaction of different types of conventional poly(amic acid) intermediates with MDI as a cross-linking agent. Subsequently, they were thermally imidized in order to obtain corresponding cross-linked polyimide structure. The results of FTIR-ATR showed that MDI can effectively react with carboxylic acid groups of PAA to form cross-linked polyimide films. TGA, FTIR-ATR and SEM analyses were carried out for characterization of cross-linked polyimide (CPI) films. Moreover, the electrical properties such as dielectric breakdown strength, dielectric constant, I– V characteristics and loss factor of MDI based cross-linked polyimides have been checked. In addition, some physical properties such as water uptake, adhesion, hardness and solubility properties of the films were investigated. The results showed that all CPI films have good insulating properties such as high dielectric breakdown voltage, low loss factor (tan δ), leakage density and excellent physical properties.

Use of Porous Membranes Modified with Polyelectrolyte Multilayers as Substrates for Protein Arrays with Low Nonspecific Adsorption

Coating of substrates with polyelectrolyte multilayers terminated with poly(acrylic acid) (PAA) followed by activation of the free -COOH groups of PAA provides a surface that readily reacts with amine groups to allow covalent immobilization of antibodies. The use of this procedure to prepare arrays of antibodies in porous alumina supports facilitates construction of a flow-through system for analysis of fluorescently labeled antigens. Detection limits in the analysis of Cy5-labeled IgG are 0.02 ng/mL because of the high surface area of the alumina membrane, and the minimal diameter of the substrate pores results in binding limited by kinetics, not mass transport. Moreover, PAA-terminated films resist nonspecific protein adsorption, so blocking of antibody arrays with bovine serum albumin is not necessary. These microarrays are capable of effective analysis in 10% fetal bovine serum.

Preparation of Mucoadhesive Chitosan-Poly(acrylic acid) Microspheres by Interpolymer Complexation and Solvent Evaporation Method I

Mucoadhesive microspheres were prepared by interpolymer complexation of chitosan with poly(acrylic acid) (PAA) and solvent evaporation method to increase gastric residence time. The chitosan-PAA complex formation was confirmed by differential scanning calorimetry and swelling study. The DSC thermogram of chitosan-PAA microspheres showed two exothermic peaks for the decomposition of chitosan and PAA. The swelling ratio of the chitosan-PAA microspheres was dependent on the pH of the medium. The swelling ratio was higher at pH 2.0 than at neutral pH. The results indicated that the microspheres were formed by electrostatic interaction between the carboxyl groups of PAA and the amine groups of chitosan. The effect of various process parameters on the formation and morphology of microspheres was investigated. The best microspheres were obtained when 1.5% of the high molecular weight chitosan and 0.3% of PAA were used as an internal phase. The optimum internal phase volume was 7%. The com oil was used as the external phase of emulsion, and span 80 was used as the surfactant. The prepared microspheres had spherical shape.

Synthesis of Photosensitive Organic−Inorganic Polymer Hybrids by Utilizing Caged Photoactivatable Alkoxysilane

Photosensitive polymer hybrids with poly(acrylic acid) (PAA) could be obtained by using caged (photosensitive protecting group modified) alkoxysilane (NVOC-U-PTEOS). Transparent polymer hybrids were prepared with UV irradiation, while the obtained materials were turbid without UV irradiation. This can be attributed to the strong ionic interaction between carboxylic acid groups of PAA and amino groups generated from NVOC-U-PTEOS by photoirradiation. The ionic interaction in polymer hybrids was confirmed utilizing FT-IR and 1H NMR, and the transparency of the polymer hybrids was evaluated by SEM.

Determination of the bioavailability of biotin conjugated onto shell cross-linked (SCK) nanoparticles.

Shell cross-linked nanoparticles (SCKs) presenting surface- and bioavailable biotin functional groups were synthesized via a mixed micelle methodology, whereby co-micellization of chain terminal biotinylated poly(acrylic acid)-b-poly(methyl acrylate) (PAA-b-PMA) and nonbiotinylated PAA-b-PMA were cross-linked in an intramicellar fashion within the shell layer of the mixed micelles, between the carboxylic acid groups of PAA and the amine functionalities of 2,2'-(ethylenedioxy)diethylamine. The hydrodynamic diameters (D(h)) of the micelles and the SCKs with different biotinylated block copolymer contents were determined by dynamic light scattering (DLS), and the dimensions of the SCKs were characterized with tapping-mode atomic force microscopy (AFM) and transmission electron microscopy (TEM). The amount of surface-available biotin was tuned by varying the stoichiometric ratio of the biotinylated PAA-b-PMA versus the nonbiotinylated PAA-b-PMA, as demonstrated with solution-state, binding interaction analyses, an avidin/HABA (avidin/4'-hydroxyazobenzene-2-carboxylic acid) competitive binding assay, and fluorescence correlation spectroscopy (FCS). The avidin/HABA assay found the amount of available biotin at the surface of the biotinylated SCK nanoparticles to increase with increasing biotin-terminated block copolymer incorporation, but to be less than 25% of the theoretical value. FCS measurements showed the same trend.

Electrochemical, spectroscopic, and thermal studies on interactions of linear poly(acrylic acid) with uranyl ions in aqueous solutions

AbstractThe formation of complexes between linear poly(acrylic acid) (PAA) and uranyl ions in aqueous solutions was studied with conductometry, potentiometry, thermal analysis, Fourier transform infrared, and luminescence spectroscopy methods. The stoichiometry of the PAA/UO complex on repeating units of a PAA basis was determined to be 2:1. IR spectroscopy studies made on solid complexes showed that the carbonyl stretching absorption band of PAA was shifted to a higher wave number, and a new band at 1749 cm−1 in the polycomplex spectrum was observed, confirming the existence of specific interactions between the carboxylate groups of PAA and metal ions. Luminescence spectroscopy studies showed an increase in the intensity of the uranyl‐ion emission spectra and new band formation at 483 nm, further confirming the interaction of UO ions with PAA in aqueous solutions. The thermal behavior of PAA/UO complexes further proved strong interactions in the complex structure. The thermal degradation of the polycomplexes included the main stages of destruction of both PAA and uranyl nitrate. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1610–1618, 2004