G. N. Fedorova

Composites of lignin and polyacrylonitrile as carbon precursors

Films of polyacrylonitrile and lignin cast from dimethylformamide were studied by dynamic thermal analysis in a self-generated atmosphere and in a vacuum. The occurrence of a thermochemical reaction of the components on heating was demonstrated. The optimal conditions of the reaction between polyacrylonitrile and lignin were determined.

Cocarbonization of polyacrylonitrile with lignin

The boundary and parameters of the thermochemical reaction of lignin and polyacrylonitrile were determined by dynamic and isothermal thermal analysis. The time, temperature, and concentration effects of formation of composites, allowing preparation of new carbonizates with enhanced heat resistance and noticeably higher carbon residue, were studied.

Thermoanalytical investigation of the role of the solvents in the preparation of polyimide films

Abstract Polyamido acid (PAA) synthesized from pyramellitic dianhydride and diaminodiphenyl-ether has been subjected to thermal analysis by a coupled simultaneous technique (TG, DTG, DTA, TVA). It was established that amide solvents—dimethyl formamide, dimethyl acetamide and N-methyl pyrrolidone—profoundly affect the process of transformation of PAA into polyimide (PI) and thermal characteristics of the latter. It was found that the thermal stability of PI depends on conditions of the preparation of PAA films (drying time and film thickness) and on the boiling point of the solvent. The necessity for a combined approach to the evaluation of thermal stability of PI is shown.

Influence of fullerene C60 on the kinetics of toluene evaporation

The kinetic dependences of the relative weight loss of the solvent from dilute solutions of fullerene C60 in toluene under ambient conditions were determined. Evaporation of the pure solvent is slower than that of the same solvent from dilute solutions (≤0.01%).

Thermochemistry of Polymers Based on Vanillic Acid

Thermal analysis of polyester and polyamides based on vanillic acid derivative — terephthaloyl-bis-(3-methoxy-4-oxy benzoic) acid has been reported. Different behaviours with the appearance of the thermal degradation, stucturization and carbonization stages were detected.Thermochemical behaviour of polymers under investigation revealed that technical lignin derivative — vanillic acid are a promise for obtaining polymer materials with good properties.

Potential activity of hydrolytic lignin in copolymerization reactions

Structural-molecular characteristics of hydrolytic lignin samples from various factories were studied and their potential activity in copolymerization with polyacrylonitrile was determined.

Polymeric Materials Derived from Vanillic Acid

Film and fibrous materials derived from vanillic acid, one of promising products from processing of industrial lignin, were prepared and characterized. Thermochemical reactions of degradation and carbonization of films and fibers of vanillic acid polyesters and polyamides were considered, and the main relationships of thermal transformations of the materials were revealed.

THERMAL ANALYSIS OF POLYAMIC ACID-FURYL ALCOHOL COMPOSITIONS

Polyamic acid (PAA) furyl alcohol (FA) and their mixtures in different ratios were investigated by DTA. The effects of the solvent and the component ratio on the thermal characteristics of the final products were established. It was shown that when the PAA-FA composition is heated, PAA is the initiator of the polymerization of FA, and the interaction in the system is profoundly affected by the component ratio and the temperature.The existence of an interaction between the components of the system was confirmed by TG, and IR and NMR spectroscopy.ZusammenfassungMittels DTA wurden Polyamidsäure (PAA), Furylalkohol (FA) und deren Gemische verschiedenen Verhältnisses untersucht. Es wurde der Einfluß des Lösungsmittels und des Komponentenverhältnisses auf die thermischen Eigenschaften der Endprodukte festgestellt. Es konnte gezeigt werden, daß beim Erhitzen der PAA-FA-Gemische PAA die Rolle des Initiators der Polymerisation von FA übernimmt und daß die Wechselwirkungen im System von Komponentenverhältnis und Temperatur grundlegend beeinflußt werden. Die Existenz der Interaktion zwischen den Komponenten des Systems wurde durch TG-, IR- und NMR-Spektroskopie bekräftigt.РезюмеМетодом ДТА изучены п олиаминовая кислота (ПАК), фурфуриловый спир (ФС) и их смеси в различных соо тношениях. Установле но влияние растворителя и соотн ошения компснентов на термические харак теристики конечных п родуктов. Показано, что при нагр евании смесей ПАК-ФС, ПАК инициирует полимеризацию ФС, а взаидействие в систе ме в значительной степени затрагивает ся соотношением комп онентов и температурой. Наличи е химического взаимодействия межд у компонентами систе мы подтверждено метода ми ТГ, ИК- и ЯМРспектрос копии.

Problems of solubility of hydrolysis lignin

Interaction of hydrolysis lignin with polyacrylonitrile in water-dimethyl sulfoxide solution in the presence of an activator was studied, and the properties of the products were examined.

Cyclization and carbonization of anionic polyacrylonitrile in the presence of carbon nanofibers

Composites based on anionic polyacrylonitrile and carbon nanofibers were studied by X-ray diffraction, differential scanning calorimetry, thermal gravimetric analysis, and electron microscopy. The effect of carbon nanofibers on the specific features of cyclization and carbonization of anionic polyacrylonitrile at temperatures of to 550°C was studied.