Esen A. Bekturov

SYNTHETIC POLYMERIC AMPHOLYTES IN SOLUTION

Abstract Polyampholytes are classified as polyelectrolytes whose macromolecules contain functional groups of acidic and basic character [1, 2]. They possess unique physicochemical properties due to the contamination of oppositely charged units in the polymer chain. The interest in studying polyampholytes arises because they include such important natural polymers as proteins and nucleic acids [3]. Biopolymers possess specific structures, functions, and properties which are fully revealed only in living organisms [4]. Nevertheless, some properties of natural polymers can be simulated by using synthetic amphoteric macromolecules.

Swelling behaviour of a non‐ionic poly(N‐vinyl‐2‐pyrrolidone) gel in a linear poly(acrylic acid) solution

The swelling behaviour of a non-ionic poly(N-vinyl-2-pyrrolidone) hydrogel in a linear poly(acrylic acid) solution upon the influence of chain length, pH, ionic strength, and water/dimethyl sulfoxide composition was studied. The sharp shrinkage of the gel volume within a narrow range of polyacid concentration takes place as a result of the formation of an intermacromolecular gel-polymer complex on the base of hydrogen bonding. According to X-ray diffraction this complex is amorphous. The formation of the gel-polymer complex is a long term process and the system reaches equilibrium within 48 h. The swelling behaviour strongly depends on the chain length of the polyacid whereas it does not depend on the ionic strength. With increasing pH value and changing water/dimethyl sulfoxide composition the gel reswelling is induced. The complex formation with poly(acrylic acid) occurs in the same way for linear and crosslinked poly(N-vinyl-2-pyrrolidone).

Interaction of synthetic polyampholytes with anionic and cationic detergents in aqueous solution

SummaryThe interaction of amphoteric macromolecules with ionic surfactants is accompanied by a strong decrease of the dimensions of the polyelectrolyte chains, but the complex particles are retained from precipitation by the presence of the hydrophylic components of the polyampholyte. The behaviour of the complex polyampholyte-detergent depends both on the nature of amphoteric copolymers and on the ionic detergents.

Complexes of Water-Soluble Polymers

The complexes of water-soluble polymers with different high- and low-molecular-weight compounds excite great interest at present. They are formed as the result of specific noncovalent interactions ...

Swelling of poly(2‐methyl‐5‐vinylpyridine) gel in linear sodium poly(vinylsulfonate) solution

The interaction of a poly(2-methyl-5-vinylpyridine) hydrochloride gel (1 a) with the aqueous solution of a linear sodium poly(vinylsulfonate) (2) was investigated. It was established that the gel collapse takes place as a consequence of the formation of a polyelectrolyte complex (1 a-2) between oppositely charged groups. The binding degree θ of the linear polymer with the gel was determined to be 0,4. The kinetics of the interaction process was examined. With increasing pH and ionic strength value a discrete phase transition both of the gel volume and of the polycomplex is induced. The collapse of the latter has increasingly sharp character.

Mössbauer Spectroscopic Studies of Complexes of Fe(III) with Nitrogen Containing Polymers

Solid complexes of poly(2-vinylpyridine), poly(2-methyl-5-vinylpyridine), poly(4-vinylpyridine), copolymers of vinylimidazole and vinylpyrrolidone with Fe(III) were studied in order to elucidate the influence of the polymeric ligand nature on the structures of polymer-metal complexes.

Solution properties of (co)polyvinylethynylpiperidols

Abstract Hydrodynamic properties of new ethynylpiperidol-based polyelectrolytes and polyampholytes were studied. Such conformational characteristics as constants of Mark-KuhnHouwink equations, unperturbed sizes, and the degree of polymer chain coiling were determined. The effect of ionic strength of solution, organic compound additions, and anion nature on molecular parameters of cationic polyelectrolytes was studied. Hydrodynamic properties of polymeric ampholytes near an isoelectric point were studied as a function of various factors. Polyampholyte macromolecules were shown to assume a compact conformation at the isoelectric point irrespective of the polymer chain length. Polyampholyte molecules unfolded at the isoelectric point with an increase of the ionic strength of the solution, which agreed with the assumption made previously.

Influence of combined magnetic and electric fields on the behaviour of polyelectrolyte hydrogel

The behaviour of polyelectrolyte gel under the influence of combined electric and magnetic fields has been studied. It is shown that the rate of gel contraction stimulated by an electric field can be significantly changed under the action of an external magnetic field. A qualitative interpretation of the observed phenomenon is given.

Cationic polymer‐metal complex formation at interfaces, solutions and hydrogels

The polymer-metal complex formation at interface, solution and hydrogels were comparatively investigated. The specific peculiarities of complexation of cationic polymers with metal ions having a various nature depending on the preparation conditions were found.

Hydrogenation catalysts based on palladium complexes with poly(vinylpyridine)

Abstract The conditions for the preparation of catalysts based on the interaction of PdCl2 with poly(vinylpyridine) were studied. The activity of polymer-metal complexes in hydrogenation can be considerably changed by variation in temperature, initial ratio of PdCl2 and polymer in solution, and contact time of the resulting complexes with the initial solution. The complex, prepared at 25°C from ethanolic solutions of poly(2-vinylpyridine) and PdCl2 (molar ratio polymer: Pd = 1:1), and kept in the initial solution for 3 days, was found to be an active catalyst for hydrogenation. The reduction of this complex with NaBH4 leads to an increase in its catalytic activity.