V. N. Zgonnik

Aggregation of fullerene C60 in N-methylpyrrolidone

Abstract Aggregation of fullerene C 60 with the solvent molecules in N -methylpyrrolidone solutions have been studied by the spectral and electrooptical methods. The time evolution of electronic absorption and photoluminescence spectra of solutions at the various initial concentrations of the solute has shown that the aggregation process is strongly concentration dependent. A comparison of spectral data with the electrooptical properties of solutions made it possible to conclude that at the concentration range −2 g cm −3 , a process of complex formation between C 60 and N -methylpyrrolidone molecules takes place.

Polyaniline composites with fullerene C60

Polyaniline-fullerene composites were prepared by the introduction of fullerene during polymerization of aniline. An investigation of the composites using FTIR and 13C NMR spectroscopy indicated interaction between fullerene and the imine groups of polyaniline. The formation of a polyaniline-fullerene complex with a structure corresponding to a doped polyaniline was proved by wide-angle x-ray scattering analysis. The conductivity of composites is more than four orders of magnitude higher than that of undoped polyaniline and that of fullerene. Improvement in the thermal stability of composites was evaluated using TGA.

Preparation and investigation of polymer-polymer compositions based on polyacrylonitrile and aromatic polyamic acid

A modification of polyacrylonitrile (PAN) was carried out. As a result, a polymer compatible (in contrast to common PAN) with polyamic acid (PAA) was obtained. PAA, PAN and their mixtures in solution and in film were investigated by viscometry, massspectrometric thermal analysis (MTA), TG and electron microscopy. The physico-mechanical characteristics of the corresponding composite films were obtained.ZusammenfassungPolyacrylnitril (PAN) wurde modifiziert, das entstandene Polymer ist (im Gegensatz zu herkömmlichem PAN) ausreichend mischbar mit Polyamicsäure (PAA). PAA, PAN und ihre Gemische wurden in Lösung und als Film mittels Viskosimetrie, massenspektrometrischer Thermoanalyse (MTA), TG und Elektronenmikroskopie untersucht. Die physisch-mechanischen Charakteristika der entsprechenden Verbundstoffilme wurden ermittelt.

Mass-spectrometric investigation of the thermal stability of polymethyl methacrylate in the presence of C60 fullerene

The thermal degradation of polymethyl methacrylate, synthesized by the method of free-radical polymerization, in a mixture with C60 fullerene has been investigated by mass-spectrometric thermal analysis. C60 suppresses the first two, low-temperature, stages in the thermal degradation of polymethyl methacrylate and thereby increases its thermal stability.

Optical properties of polydimethylphenyleneoxide free-standing films containing fullerene

The interaction of fullerene C60 with poly(2,6-dimethyl)-phenyleneoxide (PPO) in free films was studied by optical methods. The electronic structure of C60 in these polymer films was shown to have two states, with the energy state of C60 bound to PPO being independent of the C60 content. Comparison of the photoluminescence spectra of PPO-C60 and polystyrene-C60 systems makes it possible to assert that the interaction between the components of these systems occurs via π electrons of fullerene and π electrons of benzene rings of the polymers. It is assumed that C60 in the polymer exists in two forms that differ in their electronic structure: a molecular-dispersed state (in the form of complexes with the polymer) and as crystals (aggregates) of fullerene.

NSE-study of fullerene-containing polymers

Abstract Stars of Poly(styrene) chains grafted to C60 have been studied by SANS and NSE below glass transition (TG∼94∘C). In stars the arms are not condensed at fullerene surface, spreading away from C60-core. The interaction between fullerene core and polymer chains slows down the β-relaxation in arms at T=−20 to +70 ∘ C

Effect of C60 on the thermal stability of polyethylene glycol grafted to it

The thermal degradation of regular polymer networks, cross-linked by C60 molecules along the end groups of polyethylene glycol, has been investigated by mass-spectrometric thermal analysis for the example of polyethylene glycol grafted to fullerene C60. The character of the thermal degradation of the networks is substantially different from that of free polyethylene glycol and other polymer systems investigated earlier. The grafting to C60 increases the thermal stability of polyethylene glycol.

Segmental dynamics in stars of poly(ethylene oxide) chains grafted to fullerene

Abstract We have studied the structure and dynamics of star-shaped poly(ethylene-oxide) (PEO), grafted to fullerene, in D2O-solutions as compared to linear polymer. The neutron scattering gives the radius of stars having a value close to the end-to-end distance of their PEO arms. The spin-echo measurements revealed a strong damping of segmental diffusion in stars showing stretched relaxation behavior.

Anomalies of Glass Transition: Manifestation in fullerene core polystyrene stars

Segmental dynamics around Tg in the 4- and 6-arm fullerene (C60) core star-like polystyrenes with different preset arm lengths was studied by DSC as compared to that in the linear PS and PS/C60 blend. The ‘anomalies’ in glass transition behavior were found for the stars including both suppression and facilitation of segmental motion, and pronounced dynamic heterogeneity within a transition range. The results are interpreted in terms of breakdown of intermolecular cooperativity of segmental motions and PS-C60 interactions.

Optical and Electrical Properties of Star-Like Fullerene-Containing Polymers

Abstract Polystyrene and polyethyleneoxide films both containing fullerene, C60, designated as FPS and FPEO were investigated by the ellipsometry, photoluminescence spectra and electrical dc conductivity methods. The FPS and FPEO films display complex refractive index of 1.7 − 10.05 and 1.45 − 10.0 respectively. The photoluminescence maximum attributed to C60 shifted to higher photon energies proportionally to with the increase of the number of the polymer rays attached. The shift can be described by the linear relationship ΔE=004N, where ΔE is the shift in eV and N is the number of polymer rays attached. The magnitude of dc conductivity exhibited by the FPS films varied directl proportionally to molar concentration of C60