A. O. Pozdnyakov

Trapping of solvent by a C60 fullerene film

Mass spectrometry was used over a wide temperature range to compare processes of solvent (toluene) release and desorption of C60 fullerene molecules from a fullerite film formed from solution on an oxidized metal substrate. It is shown that toluene is strongly retained in the fullerite film and that it is almost impossible to remove the toluene from the film without damaging its structure. Quantitative characteristics of the toluene retention and trapping effect are determined.

Mechanism for thermal destruction of polystyrene grafted to fullerene C60

A model is proposed for the thermal destruction of polystyrene covalently bonded to C60 and this is used to explain various characteristics of its experimental mass thermograms.

Thermal stability of PMMA-fullerene C60 nanocomposite: A spectroscopic study

Molecular mechanisms responsible for a decrease in the thermal stability of poly(methyl methacrylate)-fullerene C60 nanocomposite in comparison to the pure polymer have been studied using a combination of spectroscopic techniques.

Mass spectrometry of carbon nitride C3N4

Carbon nitride has been synthesized in macroscopic amounts by means of the original method based on an ecologically safe technology using inorganic initial compounds. The product has been characterized by mass spectrometry (MS), X-ray diffraction, and quantitative chemical analysis. The MS and thermochemical data show that stoichiometry of the samples of carbon nitride obtained using the proposed method corresponds to the empirical formula C3N4.

Fullerene C60 diffusion in thin layers of amorphous polymers: Polystyrene and poly(α-methylstyrene)

The outdiffusion of fullerene C60 from submicron films of polymer-fullerene blends has been studied by thermodesorption mass spectrometry (TDMS). The energy parameters of C60 diffusion in polystyrene and poly(α-methylstyrene) were determined and compared to the parameters of desorption of C60 molecules from a multilayer film of pure fullerene deposited onto a substrate from toluene solution.

Interaction between components of poly(methyl methacrylate)-fullerene composite under UV irradiation

The interactions in the poly(methyl methacrylate) (PMMA)-fullerene (C60) system induced by UV irradiation have been studied by the methods of thermodesorption mass spectrometry and UV-Vis spectroscopy. The results are compared to the changes in the character of the kinetics of destruction of the PMMA-C60 composite.

UV photostability of PMMA-C60 fullerene composition

Thermal decomposition of pure poly(methyl methacrylate) (PMMA) and its composition with C60 fullerene before and after UV irradiation has been studied by thermodesorption mass spectrometry (TDMS). It is established that low-temperature depolymerization of UV-irradiated PMMA is suppressed in its composition with C60. Possible molecular stabilization mechanisms are discussed.

Studying polymer-on-metal friction by thermodesorption mass spectrometry

A method for determining the parameters of thermal decomposition of polymer layers transferred onto a metal counterbody surface in the course of friction has been developed on the basis of thermodesorption mass spectrometry (TDMS). The efficacy of the proposed method is demonstrated using experimental data for poly(tetrafluoroethylene), polystyrene, and poly(methyl methacrylate) (PMMA). Using TDMS, it is possible to distinguish between damaged and intact molecules transferred in the course of friction in a relatively soft regime. TDMS data revealed differences in the character of thermal decomposition in the layers transferred during the friction of pure PMMA and PMMA-fullerene (C60) composition on steel.

Thermal desorption states of C60 fullerene molecules in polymer matrices

Polymer-C60 fullerene composite coatings are studied using thermal desorption mass spectrometry. It is found that thermal desorption spectra of C60 fullerene molecules can exhibit several resolved peaks (at a specified heating rate) corresponding to thermal desorption states. The relative intensity of the thermal desorption peaks depends on the procedure used for preparing the composite coatings, in particular, on the time of sedimentation of the polymer-fullerene suspension. The occurrence of different stages in thermally stimulated desorption of C60 fullerene molecules is explained by the fact that the fullerene molecules can exist in several phase states characterized by different densities and degrees of ordering in the polymer matrix.

Thermally stimulated desorption of C60 and C70 fullerenes from rigid-chain polyimide films

Polyimide-fullerene composite thin coatings are investigated using thermal desorption mass spectrometry in the temperature range 20–800°C. It is found that, at temperatures below the temperature of decom-position of the polymer matrix, thermally stimulated desorption of fullerene molecules is limited by the diffusion of fullerene molecules in the matrix. The diffusion coefficients and activation energies of diffusion of C60 and C70 fullerene molecules are determined from the experimental data on thermally stimulated desorption in the framework of several approaches. It is revealed that the diffusion of C70 molecules in the polyimide matrix is more hindered than the diffusion of C60 molecules in the same matrix.