Gennady Zaikov

Hydrolytic Degradation of Poly(3-hydroxybutyrate), Polylactide and their Derivatives: Kinetics, Crystallinity, and Surface Morphology

Hydrolytic degradations of biodegradable poly(3-hydroxybutyrate) (PHB), polylactide (PLA) and their derivatives were explored by kinetic and structure methods at 37 and 70°C in phosphate buffer. It was revealed the kinetic profiles for copolymer PHBV (20% of 3-hydroxyvalerate) and the blend PHB-PLA (1:1 wt. ratio). The intensity of biopolymer hydrolysis depending on temperature is characterized by total weight loss and the viscosity-averaged molecular weight decrement (ΔMW) as well as by WAXS and AMF techniques. Characterization of PHB and PHBV includes both ΔMW and crystallinity evolution (x-ray diffraction) as well as the AFM analysis of PHB film surfaces before and after aggressive medium exposition. The degradation is enhanced in the series PHBV < PHB < PHB-PLA blend < PLA. The impact of MW on the biopolymer hydrolysis is shown.

Biodegradation and Medical Application of Microbial Poly(3-Hydroxybutyrate)

This review is designed to be a comprehensive source for biodegradable polymer: poly(3-hydroxybutyrate) research, including fundamental structure/property relationships and biodegradation kinetics for samples of different geometry. In addition to presenting the scientific framework for the advances in PHB research, this review focuses on applications of PHB in biomedicine and environment with a discussion on commercial applications and health/safety concerns for biodegradable materials.

Physical Principles of the Conductivity of Electrically Conductive Polymer Composites (Review)

The role of the structural peculiarities of electrically conductive polymer composites is considered in this review. Different conceptions of the nature of the conductivity and the mechanisms of charge transfer in heterogeneous structures are presented. Experimental results obtained by different scientists are only partially in accord with existing theoretical models. It is suggested that lack of information on various physical and chemical factors influencing the processes of electrical current formation in polymer composites is one of the main reasons for the divergence between theory and experimental results, among which the rate of the inter- and intra-phase interactions in composites may be considered very important. The conductivity of systems with binary conducting fillers is also considered.

Catalytic Oxidation of Ethylene Glycol by Dioxygen in Alkaline Medium. The New Example of One-Stage Oxidative Cleavage of С‒С Bond

Reaction of low temperature oxidations of ethylene glycol (EG) by molecular oxygen in the presence of salts of bivalent copper and alkali both in water and in waterless solutions was investigated. It was found that at low (close to room) temperatures for the process carrying out in waterless solutions the basic product of EG oxidation is formic acid. Rising the temperature from 290–315 K to 350–360 K or carrying out the reaction in water-containing solutions leads to sharp change of a direction of reaction. EG in these conditions is oxidized with primary formation of glycolic acids salts. The change of direction of reaction is connected, apparently, with decrease stability of chelate complexes of Cu2+-ions with dianionic form of EG. The mechanism of glycolic acids formation includes, possibly, a stage of two-electronic reduction of О2 in reaction of dioxygen with monoanionic forms of EG, coordinated on Cu2+-centers.

XI International Conference Polymeric Materials 2004: Properties, Processing, Modification, Application

The XI International Conference on Polymeric Materials 2004 (Properties, Processing, Modification, Application) was held in Halle/Saalle (Germany) on the campus of Martin Luther University (Halle-Wittenberg) from September 29–October 1, 2004. The Conference was organized by Martin-Luther Universitat, Halle-Wittenberg, Institut fur Werkstoffwissenschaft, Institut fur Polymerwerkstoffe e.V. (IPW), Hallescher Bezirksverein des VDI Arbeitskreis Werkstoff- und Kunststofftechnik.

Polymers in Europe

The VI National Congress on Chemical Technology in Turkey was held in Bornova Izmir (Turkey) on the campus of Ege University in the period September 7– 10, 2004. Profs. Erden Alpay (Ege University), Mehmet Riza Altiokka (Anatolian University, Ankara), Suheyda Atalay (Ege University), Devrim Balkose (Izmir Institute of Technology), Ertugrul Barka (KMO Ege Bolge Co.), Cumhur Buyukakinci (Polinas Co.), Ahmet Cetinbudaklar (Mopak Co.), Muhsin Ciftcioglu (Izmir Institute of Technology), Timur ERK (Chemical Society of Turkey), Murat Ipekcioglu (Aromel Co.), Gungor Kavadarli (EBSO Co.), Zehra Ozcelik (Ege University), Kivanc Turkel (ALKIM Co.), and Sevgi Ulutan (Ege University) were members of the organizing committee. About 450 participants from 28 research centers of Turkey took part in this congress. There were four invited speakers from USA, Russia and Israel. About 200 sectional reports and 120 posters were included in the program of the congress. In the opening ceremony, the chairman (chairlady) of the con...

Columns: Polymers in Europe: Symposium: “Actual Problems of Chemistry and Physics of Functionalized and Mesophase Polymers”

The Symposium “Actual Problems of Chemistry and Physics of Functionalized and Mesophase Polymers” was held on November 3, 2004. The symposium was organized by RAS, A. V. Topchiev Institute of Petrochemical Synthesis (IPCS) and Scientific Council on High-Molecular Weight Compounds of RAS. The CORIUM International Co (Redwood City, NY, USA) and TNO (Institute of Innovations in the Field of Energetic Problems) (The Netherlands) were sponsors of this symposium. Prof. V. G. Kulichikhin was chairman of the symposium. L. I. Valuev, V. V. Volkov, I. V. Ermakov, L. I. Ivanova, I. S. Kalashnikova, A. D. Litmanovich, A. Ya. Nazarenko, I. A. Oreshkin, R. V. Tal’rose. G. F. Tereschenko, and S. N. Khadzhiev were members of the Organizing Committee

Conference Report: 11th International Conference for Renewable Resources and Plant Biotechnology NAROSSA®

The 11th International Conference for Renewable Resources and Plant Biotechnology was held in Poznan, Poland June 6–7, 2005 at the Institute of Natural Fibres (INF) under the patronage of the Minister of Agriculture of Saxony-Anhalt, Germany. The Conference was sponsored by Pilot Pflanzeneoltechnologie Magdeburg e.V (PPM), Dr. Weigel, Anlagenbau GmbH (Germany), BMD (Biomitteldeuschland GmbH, Halle-Saale, Germany), OHMI-Consulting GmbH (Magdeburg, Germany), “Cellubast” (Centre of Excellence on Natural Lignocellulosic Fibrous Raw Materials, INF). Specialist partners on the conference were Innoplanta e.V. (Gatersleben, Germany), INF, BioPro AG (Biological Products), Magdeburg, Germany and Forschungs-und Beratungszentrum fur Maschinen-und Energiesysteme e.V. (FBZ), An-Institut an der Hochschule Merseburg (FH), Germany.

Conference Report: Second Workshop on Polymer and Biopolymer Analysis, Degradation, and Stabilization

The second workshop on polymer and biopolymer analysis, degradation, and stabilization was held at the University of Alicante (Alicante, Spain) on September 24-26, 2003. The organizer of this conference was the Departamento de Quimica Analitica, Nutricion y Bromatologia. The co-organizer was the Department of Civil and Environmental Engineering University of Perugia (Italy). The conference was sponsored by the Universidad Politechnica de Valencia, Instituto Technologico del Plastico (AIMPLAS) and the Saving Bank of Spain (BANCAJA). Dr. Alfonso Jimenez (University of Alicante) was the chairman of the organizing committee.

Short Communication: Estimation of Thermodynamical Parameters of the Activation Complex and Initial Reagents for Reactions of Thermolysis

The linear dependences between entalpy and entropy of formation of the activation complex and such characteristics for preliminary substances are researched for reactions of thermolysis of nitrogen compounds. Those dependences allows us to estimate the kinetic parameters of decomposition of nitrogen compounds. Nitrogen compounds (R1 - N2 - R2) are widely applied in laboratory practice as the initiators and photoinitiators of radical chain reactions. They are very convenient objects for studying of the cell effect. Sometimes for chemists it is very interesting to predict the influence of different substitutents for thermal stability of nitrogen compounds before initiation of synthesis.