Interactions of di- and trivalent anionic azo dyes with polycations of integral type

The spectral changes of Crystal Ponceau 6R and Ponceau 4R induced by the interaction with polycations having N,N-dimethyl-2-hydroxypropane-1,3-diylammonium chloride units in the main chain were followed. The stoichiometry of the polycation-dye complex related to the dye structure was elaborated by UV-VIS spectrophotometry and viscosimetric measurements. Formation of a tricomponent complex between the polycation/dye complex and poly(sodium acrylate) was also revealed.     

Ionic organic/inorganic materials. I. Novel cationic siloxane copolymers containing quaternary ammonium salt groups in the backbone

The synthesis and characterization of some novel cationic siloxanes copolymers containing quaternary ammonium salt (QAS) groups in the backbone is reported in this article. One cationic oligomer having QAS in the backbone and reactive groups like 2,3‐epoxypropyl and 2‐hydroxy‐3‐chloropropyl (RCO) as well as 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane or α,ω‐bis(3‐aminopropyl)oligodimethylsiloxane (AP) were used as precursors for this goal. Elemental analysis, IR and ¹H NMR spectroscopy, thermogravimetric analysis, and X‐ray photoelectron spectroscopy were used to characterize the obtained copolymers. The thermal stability of the cationic siloxane copolymer increased when the siloxane oligomer having a high number of siloxane units in the chain (AP) was used as a precursor. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3570–3578, 2002     

Adsorption of poly(vinyl formamide-co-vinyl amine) onto silica particle surfaces and stability of the formed hybrid materials

In order to produce silica/polyelectrolyte hybrid materials the adsorption of the polyelectrolyte poly(vinyl formamide-co-vinyl amine), P(VFA-co-VAm) was investigated. The adsorption of the P(VFA-co-VAm) from an aqueous solution onto silica surface is strongly influenced by the pH value and ionic strength of the aqueous solution, as well as the concentration of polyelectrolyte. The adsorption of the positively charged P(VFA-co-VAm) molecules on the negatively charged silica particles offers a way to control the surface charge properties of the formed hybrid material. Changes in surface charges during the polyelectrolyte adsorption were studied by potentiometric titration and electrokinetic measurements. X-ray photoelectron spectroscopy (XPS) was employed to obtain information about the amount of the adsorbed polyelectrolyte and its chemical structure. The stability of the adsorbed P(VFA-co-VAm) was investigated by extraction experiments and streaming potential measurements. It was shown, that polyelectrolyte layer is instable in an acidic environment. At a low pH value a high number of amino groups are protonated that increases the solubility of the polyelectrolyte chains. The solvatation process is able to overcompensate the attractive electrostatic forces fixing the polyelectrolyte molecules on the substrate material surface. Hence, the polyelectrolyte layer partially undergoes dissolving process.     

Chitosan based nonstoichiometric polyelectrolyte complexes as specialized flocculants

The aim of this work was to evaluate the flocculation of kaolin by using positively charged nonstoichiometric interpolyelectrolyte complex (N-PEC) nanoparticles formed by the interaction of chitosan with poly(sodium 2-acrylamido-2-methylpropanesulfonate) (NaPAMPS) and two random copolymers of AMPS with t-butyl acrylamide, comparative with chitosan. The flocculation efficiency was evaluated by optical density at 500 nm. The N-PEC nanoparticles were more effective than chitosan in the kaolin separation, especially at low molar ratios between charges, when the flocculation window was more then double at an optimum dose lower than that of chitosan. The main advantage of N-PECs is the increase of critical concentration for kaolin re-stabilization, the N-PEC particles adsorbed on the kaolin surface protecting them more efficient against re-dispersion. The influence of low molar mass electrolytes on the flocculation with N-PECs was also investigated.     

Viscometric study of poly(sodium 2-acrylamido-2-methylpropanesulfonate) and two random copolymers

Effects of the polyanion synthesis conditions and composition on the viscometric behavior of poly(sodium 2-acrylamido-2-methylpropanesulfonate) (PAMPS) and two random copolymers, poly(sodium 2-acrylamido-2-methylpropanesulfonate-co-methylmethacrylate) (PAMPSMM) and poly(sodium 2-acrylamido-2-methylpropanesulfonate-co-tert-butylacrylamide) (PAMPSTBA), in a wide range of concentrations were reported in this paper. The experimental data obtained in salt-free aqueous solution were plotted in terms of the Fuoss and the Rao equations in order to obtain the intrinsic viscosity values. The C∗ values obtained as the reciprocal of the intrinsic viscosity were compared with the experimentally determined values and with those calculated according to the Odijk theory. An acceptable agreement between C∗ values obtained by different approaches was found for the PAMPS samples with high molar masses (0.83 × 10⁶-1.4 × 10⁶ g/mol). For the same charge density and the same concentration the reduced viscosity values were higher for PAMPSMM comparative with PAMPSTBA indicating a higher chain extension of the former copolymer.     

Synthesis of New Modified with Rhodamine B Peptides for Antiviral Protection of Textile Materials

Here we report on the synthesis and characterization of three new N-modified analogues of hemorphin-4 with rhodamine B. Modified with chloroacetyl, chloride cotton fabric has been dyed and color coordinates of the obtained textile materials were determined. Antiviral and virucidal activities of both the peptide-rhodamine B compounds and the dyed textile material were studied. Basic physicochemical properties (acid-base behavior, solvent influence, kinetics) related to the elucidation of structural activity of the new modified peptides based on their steric open/closed ring effect were studied. The obtained results lead to the conclusion that in protic solvent with change in pH of the environment, direct control over the dyeing of textiles can be achieved. Both the new hybrid peptide compounds and the modification of functionalized textile materials with these bioactive hemorphins showed virucidal activity against the human respiratory syncytial virus (HRSV-S2) and human adenovirus serotype 5 (HAdV-5) for different time intervals (30 and 60 min) and the most active compound was Rh-3.     

Chloromethylated polystyrene reaction with tris(2-hydroxyethyl)amine. I. Crosslinked polymers prepared by chloromethylated polystyrene with tris(2-hydroxyethyl)amine

A multifunctional crosslinked polymer resulted from a chloromethylated polystyrene reaction with tris(2-hydroxyethyl)amine. A benzyl chloride reaction (chosen as a structural unit model) with tris(2-hydroxyethyl)amine was investigated to explain the reasons for the crosslinking. Amino-ethers and tris(2-hydroxyethyl)amine hydrochloride in addition to ammonium quaternary salt were isolated from this reaction. The formation of amino-ethers proved that an ammonium quaternary salt rearrangement also takes place during the quaternization reaction. This rearrangement leads to chloromethylated polystyrene during its reaction with tris(2-hydroxyethyl)amine.     

Ionic organic/inorganic materials. III. Stimuli responsive hybrid hydrogels based on oligo(N,N‐dimethylaminoethylmethacrylate) and chloroalkyl‐functionalized siloxanes

Ionic organic/siloxane networks containing quaternary ammonium salt (QAS) sequences in the cross‐linking bridges were obtained by the Menshutkin reaction of oligo(N,N‐dimethylaminoethylmethacrylate) (ODMAEM) with a telechelic chloroalkylated siloxane (CAS), such as 1,3‐bis‐(chloromethyl)‐1,1,3,3‐tetramethyldisiloxane, 1,3‐bis‐(chloropropyl)‐1,1,3,3‐tetramethyldisiloxane, and α,ω‐bis(chloromethyl) oligodimethylsiloxane. The resulted structures were investigated by Fourier transform infrared spectroscopy emphasizing the presence of both organic and siloxane moieties. The thermogravimetric analysis under inert atmosphere of the networks, besides the thermal stability, gave also information on the composition of hybrid hydrogels. The morphology of the lyophilized networks was evidenced by environmental scanning electron microscopy, as a function of CAS structure and CAS: ODMAEM feed molar ratio. The swelling response of the ionic networks in water as a function of pH and counterion nature and concentration as well as the water vapors sorption capacity in dynamic regime were evaluated. The properties of the ionic hybrid hydrogels were correlated with the reactants feed molar ratio and concentration of the reaction mixture, CAS type, and the presence of a catalyst. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009