V. M. Denisov

Structural Parameters of Cellulose Produced by Acetobacter Xylinum and Their Variation in the Course of Drying of Gel Films

The cellulose-producing power of the VKM V-800 Acetobacter xylinum strain under conditions of static culture was studied. The culture medium was optimized with the aim to increase the cellulose yield and obtain highly crystalline cellulose I with molecular weight of about 5 × 105.

A model of supermolecular structure of stiff-chain polyimide copolymers and composites☆

Abstract Microstructure and molecular packing in stiff-chain polyimide copolymers and composites of various composition was studied by PMR, X-ray diffraction, and also by calculating the diffraction patterns for model systems. Copolymers of different microheterogeneity were synthesized; it is shown how to characterize the microheterogeneity in the stage of poly(amic acid) by means of PMR and in the polyimide stage by means of X-ray diffraction measurements. A generalized model has been proposed for the domain structure of polyimide copolymers and composites, which shows the latter to be molecular composites and elucidates the reasons underlying the improvement of physico-mechanical over those of homopolymers.

Study of the interaction of organometallic compounds with electron donors by the PMR method. 2. Complex formation of diethylzinc with tetrahydrofuran, diethyl ether, propylene oxide, and propylene sulfide

1. Complexes of diethylzinc with THF, diethyl ether (DEE), propylene oxide (PO), and propylene sulfide (PS) are appreciably dissociated in solutions of cyclohexane, and in the case of dilution, the degree of dissociation increases, which is manifested in the PMR spectra. 2. On the basis of an estimate of the equilibrium constants of the reaction of complex formation and the spectroscopic effect, the donors studied are arranged in the following series according to decreasing strength of their complexes with diethylzinc: THF>PO>PS ≥DEE.

Synthesis of Branched Chemodegradable Homopolymers of N-(2-Hydroxypropyl)methacrylamide

Branched water-soluble N-(2-hydroxypropyl)methacrylamide homopolymers containing interchain urethane links were prepared. The hydrodynamic and molecular-weight characteristics of the branched homopolymers and the rate of their hydrolysis under the conditions close to those of a living body (saline, pH 7.0, 37°C) were determined.

Synthesis of N-Vinylpyrrolidone-Crotonic Acid-2-Hydroxyethyl Methacrylate Terpolymers as Carriers of Biologically Active Substances

Water-soluble N-vinylpyrrolidone-crotonic acid-2-hydroxyethyl methacrylate terpolymers, potential polymeric carriers for biologically active substances, were prepared. The composition of the terpolymers was determined, their chemical structure was confirmed, and their hydrodynamic characteristics and structural features in aqueous solutions were studied.

Structure and Transport Properties of Films of Mixed Cellulose Esters

Cellulose acetomyristates of varied composition were studied. The sample volume abnormally increases in high-temperature stretching and after swelling in benzene. Cellulose acetomyristates can be used as membranes for separating aromatic and aliphatic hydrocarbons.

Synthesis of Water-Soluble Chemodegradable N-Vinylpyrrolidone-Crotonic Acid-2-Hydroxyethyl Methacrylate Terpolymers Containing Interchain Urethane Cross-Links, as Carriers of Substances with Antimicrobial Activity

Water-soluble branched N-vinylpyrrolidone-crotonic acid-2-hydroxyethyl methacrylate terpolymers containing labile interchain urethane cross-links were prepared. Their molecular-weight characteristics were determined, and the hydrolytic stability under conditions close to those in a living body was evaluated. Polymeric salts of gentamicin were prepared from linear and branched chemodegradable N-vinylpyrrolidone terpolymers.

Salts of the Antibiotic Gentamicin with Carboxyl-Containing N-Vinylpyrrolidone Copolymers

One way of decreasing the toxicity of biologically active substances (BAS), including antibiotics and antiseptics, is to form complexes (salts) with low-toxicity water-soluble reactive copolymers of N-vinylpyrrolidone (VP) [1 – 4]. Reduction in toxicity is particularly relevant to aminoglycoside antibiotics, especially gentamicin, a substance consisting of a mixture of homologs – C1, C1A, and C2, of general formula I.