Radiation grafting from binary monomer mixtures. I. Vinyl ether of monoethanolamine and vinyl ether of ethyleneglycol

Gamma-radiation grafting of vinyl ether of monoethanolamine and vinyl ether of ethyleneglycol (VEEG) on polyethylene films has been studied from binary monomer mixtures. The effect of co-monomer composition and total exposure radiation dose on the grafting process is investigated. A combination of potentiometric and gravimetric techniques is applied to determine the grafting degree of each monomer in the final graft copolymer. The presence of more active monomer VEEG in the mixture was found to enhance the grafting of both monomers because the increasing of copolymerization rate which in turn increases the total grafting degree. The modification of the hydrophilic properties of the graft copolymer is studied by examining the grafted films for water- and copper (II) ions uptake.     

Stabilization of water/n‐hexane emulsions by amphiphilic copolymers based on vinyl ethers and their polycomplexes with poly(acrylic acid)

Amphiphilic random copolymers based on vinyl ether of ethylene glycol and vinyl butyl ether as well as their polycomplexes with poly(acrylic acid) were studied as polymeric reagents for the stabilization of water/n‐hexane emulsions. The emulsion stability strongly depended on the content of vinyl butyl ether in the copolymers as well as their concentration in solution. The more hydrophobic copolymers stabilized emulsions more efficiently. An increase in the temperature and the addition of inorganic salts reduced the emulsion lifetime. The formation of interpolymer complexes between the copolymers and poly(acrylic acid) significantly influenced the stability of the emulsions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2625–2632, 2004     

Polyelectrolyte complexes of soluble poly-2-[(methacryloyloxy)ethyl]trimethylammonium chloride and its hydrogels with poly(acrylic acid)

The complex formation of poly-2-[(methacryloyloxy)-ethyl]trimethylammonium chloride (PMADQUAT) with poly(acrylic acid) (PAA) of different molecular weights has been studied in aqueous solutions by potentiometric, viscometric, turbidimetric and FTIR spectroscopic methods. The formation of insoluble non-stoichiometric polyelectrolyte complexes has been shown. The stability of polyelectrolyte complexes in solutions of different pH and ionic strength has been evaluated. The formation of polyelectrolyte complexes between hydrogels of PMADQUAT and linear PAA of different molecular weights has been studied. It was shown that the molecular weight of PAA considerably affects the kinetics of interaction as well as the final state of gel-polymer complex.     

Interpolymer complexes of copolymers of vinyl ether of diethylene glycol with poly(acrylic acid)

 The complex formation reactions of poly(vinyl ether of diethylene glycol) as well as vinyl ether of diethylene glycol–vinyl butyl ether copolymers with poly(acrylic acid) have been studied in aqueous and alcohol solutions. The formation of interpolymer complexes which were stabilized by hydrogen bonds was shown. The effects of molecular weight of poly(acrylic acid) and the nature of the nonionic polymer on the composition and stability of interpolymer complexes were clarified. The critical pH values of complexation were determined for different systems with various molecular weights and hydrophobic–hydrophilic balances. The stability of the interpolymer complexes formed in aqueous and alcohol solutions with respect to dimethylformamide addition was evaluated. The role of hydrophobic interactions and the presence of active groups on stability of the interpolymer complexes is discussed. Received: 23 July 2001 Accepted: 27 September 2001     

Collapse of Poly(methacrylic acid) Hydrogels in Response to Simultaneous Stimulation by an Electric Field and Complex Formation

Complex formation of poly(methacrylic acid) hydrogels with linear poly(ethylene glycol) has been studied at different pH values and in the presence of an electric field. The fastest contraction of the gel samples was observed under simultaneous action of electric field and complex formation.

Dependence of the volume ratio V/V₀ of PMAA sample on time: Sample in the absence of an electric field immersed in 0.1 M PEG solution at (1) pH 8.2, (2) at pH 5.1, and in the presence of an electric field (3) in water and (4) 0.1 M PEG solution at pH 5.1.     

pH effects on the complexation, miscibility and radiation-induced crosslinking in poly(acrylic acid)-poly(vinyl alcohol) blends

The effect of pH on the complexation of poly(acrylic acid) with poly(vinyl alcohol) in aqueous solution, the miscibility of these polymers in the solid state and the possibility for crosslinking the blends using gamma radiation has been studied. It is demonstrated that the complexation ability of poly(vinyl alcohol) with respect to poly(acrylic acid) is relatively low in comparison with some other synthetic non-ionic polymers. The precipitation of interpolymer complexes was observed below the critical pH of complexation (pH(crit1)), which characterizes the transition between a compact hydrophobic polycomplex and an extended hydrophilic interpolymer associate. Films prepared by casting from aqueous solutions at different pH values exhibited a transition from miscibility to immiscibility at a certain critical pH, pH(crit2), above which hydrogen bonding is prevented. It is shown here that gamma radiation crosslinking of solid blends is efficient and only results in the formation of hydrogel films for blends prepared between pH(crit1) and pH(crit2). The yield of the gel fraction and the swelling properties of the films depended on the absorbed radiation dose and the polymer ratio. [Diagram: see text] SEM image of an equimolar PAA-PVA blend cast from a pH 4.6 solution.     

Factors affecting the complexation of polyacrylic acid with uranyl ions in aqueous solutions: A luminescence study

A study was carried out in aqueous solutions using luminescence technique to investigate the effects of pH, salt concentration, and temperature on the polyacrylic acid/uranyl ion (PAA/UO) complex formation as well as competitive phenomena of enhancement and quenching effects on photoexcited state of uranyl ions. It was found that excess of H⁺ and OH^? is not favorable for complexation between uranyl ions and polymer. Added nitrate salts of Na⁺ and K⁺ had significant enhancement effect on emission spectra of PAA/UO complex. These results indicated that the metal ion/polymer chain complex collapsed by addition of salts and then complex became more compact with consequent phase separation. No significant effect of temperature on the PAA/UO complex stability has been observed between 25–50 °C. The quenching rate constants obtained from Stern–Volmer plots were found to be in the order of k_q(H⁺) >> k_q(K⁺) > k_q(Na⁺). © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2737–2744, 2005     

Interpolymer Complexes of Water‐Soluble Nonionic Polysaccharides with Polycarboxylic Acids and Their Applications

Literature data as well as our own experimental results devoted to the complexation of polycarboxylic acids with various water‐soluble polysaccharides (methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, starch, and dextran) by means of hydrogen bonding are systematized and analyzed. The specific peculiarities of interpolymer complexes based on polysaccharides‐polycarboxylic acids are demonstrated. The perspectives for the application of these interpolymer complexes are considered. It was shown that these materials possess good biocompatibility and adhesive properties. The promising directions for further study of interpolymer complexes between polycarboxylic acids and nonionic polysaccharides as well as existing gaps in the knowledge in this field are pointed out.

Formation of compact IPCs and hydrophilic interpolymer associates.     

Hydrophilic Films Based on Blends of Poly(acrylic acid) and Poly(2‐hydroxyethyl vinyl ether): Thermal,Mechanical, and Morphological Characterization

Hydrophilic films based on blends of poly(acrylic acid) and poly(2‐hydroxyethyl vinyl ether) were prepared by casting. The characterization of the films was performed by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM). It was shown that an increase of poly(2‐hydroxyethyl vinyl ether) content in the blends considerably decreases the glass transition temperature of the samples. The films containing 10 and 20 mol‐% of poly(2‐hydroxyethyl vinyl ether) show behavior of polymers in the glassy state, but a further increase of nonionic polymer content in the blend (30–50 mol‐%) provides the mechanical properties typical of a rubbery state. The content of water traces in the films has a significant effect on the mechanical properties of the materials.

Normalized DSC thermograms of PAA:PHEVE films. [PAA]:[PHEVE] = 90:10 (1), 80:20 (2), 70:30 (3), 60:40 (4), 50:50 mol‐% (5).     

Interpolymer complexes of poly(acrylic acid) with poly(2-hydroxyethyl acrylate) in aqueous solutions

Complexes formed from poly(acrylic acid) and poly(2-hydroxyethyl acrylate) were studied in aqueous solutions by viscometric, turbidimetric, FTIR spectroscopic, and thermogravimetric analysis methods. The formation of interpolymer complexes stabilized by hydrogen bonds was observed. It was found that the compositions of these interpolymer complexes are strongly dependent on the concentration of polymers, the order of mixing the solutions, and the pH. It was demonstrated that the complexation ability of poly(2-hydroxyethyl acrylate) is relatively low compared to other known nonionic water-soluble polymers. However, it can be significantly increased via hydrophobic modification of the poly(acrylic acid) using cetyl pyridinium bromide.