Addition Of Fullerene Research Articles

Encapsulation of pristine fullerene C60 within block copolymer micelles through interfacial instabilities of emulsion droplets

We report a facile and versatile strategy to encapsulate pristine fullerene (C60) within spherical or wormlike block copolymer micelles through interfacial instability of emulsion droplets. C60 and amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) were firstly dispersed in chloroform. The resulting solution was emulsified with aqueous sodium dodecylsulfate solution by simply shaking it. The emulsion droplets were collected in an open container and the solvent was allowed to evaporate. During solvent evaporation, the emulsion droplets became unstable and broke into tiny droplets, i.e., interfacial instabilities occurred, triggering the formation of uniform spherical micelles with encapsulated fullerenes in the micellar cores. More interestingly, fullerene addition induced a morphological transition from cylindrical micelles to string-of-vesicles and then to spherical micelles with increasing fullerene contents of 5wt%, 10wt%, and 30wt%, respectively. We show that the optical properties of the confined C60 molecules can be modified by varying the quantity of fullerenes in the micelles. In addition, poly(3-hexylthiophene) (P3HT) can be co-encapsulated with C60 into the micellar cores when P3HT was dissolved in the initial polymer solution prior to emulsification. Presence of C60 in the micellar cores induced fluorescence quenching of P3HT due to photoinduced energy transfer from electron-donating P3HT to electron-accepting C60 molecules. Hybrid micelles with well-controlled structures and components can be potentially useful in the area of photodynamic therapy and photovoltaics.

Effects of fullerene derivatives on the gas permeability of thermoplastic polyurethane elastomers

ABSTRACTIn an effort to improve the gas barrier properties of thermoplastic polyurethane (TPU) elastomers, fullerene derivatives were added as fillers, and the resulting O2 and CO2 permeabilities were analyzed. The addition of 5 wt % polyhydroxylated fullerene {fullerenol [C60(OH)n] mixture, where n = 6–12} decreased the gas permeability by approximately 10–20%. According to the hole volumes computed with the results from positron annihilation lifetime spectroscopy, the addition of fullerene derivatives did not produce any changes in the hole volumes of the TPUs. Thus, the reduction in the TPU gas permeability was not caused by changes in the hole volumes. Instead, an inhibited diffusion of gas molecules by fullerene particles was deduced as the cause of the decrease in gas permeability from changes in the diffusion coefficient with temperature. The addition of urethanized fullerene, prepared through the chemical modification of fullerenol, markedly affected the TPU gas barrier properties. As compared to fullerenol addition, the gas barrier properties improved approximately fourfold for O2 and approximately fivefold for CO2. These results suggest that the dispersability of urethanized fullerene in TPU was higher than that of fullerenol. We found that the gas barrier properties were independent of the structure of polyol. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39986.

An investigation of the structural and thermodynamic properties of polystyrene fullerene-containing films

Polystyrene films doped with small additives of fullerenes (w = 0–1 × 10−3) are obtained. The nonmonotonic dependence of the glass transition point on composition with a minimum at w = 1 × 10−4 is revealed by the DSC method. It is concluded that there is a plasticizing action of small amounts of filler at w 1 × 10−4. It is established by small-angle X-ray scattering that composites containing fullerenes in the amount w > 1 × 10−4 are characterized by the greatest mobility of the segments in the modified polymer chains.

Oscillatory shear rheology of polystyrene melts filled with carbon black and fullerene

Fullerene C60 and submicrometre sized particles of carbon black were used to investigate the size effect of filler particles on the rheological behaviour of polydisperse polystyrene melts. The addition of 5 wt-% carbon black increased the viscosity of all the composite melts relative to their polymer matrixes. The effect of 5 wt-% fullerene nanoparticles on the viscosity of composites depended on the molecular weight distribution of the polymer matrixes. In the polymer with a high fraction of polymer chains below the critical molecular weight for entanglement, the fullerene addition increased the viscosity, similar to carbon black addition. As the molecular weight distribution of the polymer matrix moved to higher values, the influence of fullerene addition on melt viscosity changed, and the viscosity of the nanocomposite was similar to that of the polymer matrix. The effect of fullerene addition on the melt viscosity of the coarse particle composite was also investigated.

THERMOOXIDATIVE STABILITY OF JET FUEL WITH FULLERENES AS AN ADDITIVE

Heating of fuels in presence of oxygen reduces their thermal-oxidative stability, leads to a solid phase in the form of sludge and tar, which, sedimented at the details of the fuel system, change its characteristics and cause contamination of fuel filters and injectors, spool control sticking, reduce efficiency of heat exchangers. Nanomaterials, performance of which is considerably superior to the natural materials, are the basis for the movement of humanity's progress. Therefore, with a develpoment of technologies it has become necessary to carry out a research of modified additives – fullerens, to improve an oxidative stability of fuels. We have carried out an investigation of thermal-oxidative stability of fuel RT as a function of additive C 60 concentration. The results has shown that even 0,043 g/l fullerene addition as an antioxidant, reduces the amount of sediment in the fuel almost by half. Usage of fullerenes for improvement of petroleum products performance properties is a promising area of research.

Mechanisms of nonlinear transmission in solutions and thin films of the COANP-C70 fullerene system

The process of nonlinear optical transmission in solutions and thin films of 2-cyclooctylamine-5-nitropyridine (COANP) sensitized by C70 fullerene additions has been studied. Possible mechanisms responsible for the attenuation of light flux intensity are considered. Comparative DSC data for a pure COANP and one sensitized by C70 fullerene are presented that confirm the existence of one of these mechanisms.

Effect of fullerene black additives on boundary sliding friction of steel counterbodies lubricated with mineral oil

The effect of small additives of fullerene black (from 0.01 to 1 wt %) on the antifriction and anti-wear properties of a steel-steel pair lubricated with I-40A oil under boundary friction is studied. Based on the results of small-angle and wide-angle X-ray scattering it is suggested that more intensive dispersion of fullerene black in oil results in exposure of the crystalline grains of fullerene C60 and graphite.

Use of fullerene additions for modification of chemical absorbers

The characteristics of lime chemical absorber, both conventional and modified with fullerenes, were examined under dynamic conditions (kinetic characteristics of the CO2 uptake, water retention capacity, and pore structure).

DSC investigation of the polystyrene films filled with fullerene

Abstract Polystyrene composite films with different content of C60 + C70 fullerene mix have been obtained from o-xylene solutions. The mass fraction of fullerene was varied from 0.01 to 0.1 mass%. The glass transition temperatures and specific heat capacities in range of 293–423 K have been determined for the films by DSC method. The plasticization of the polymer is observed in thermal properties of the films under influence of small fullerene additions. The values of Tg and CP decrease and thermal coefficient of heat capacity b increase as fullerene content increases up to 0.02 mass%. The effect of interaction between polymer and fullerene molecules on thermal properties becomes evident at higher fullerene content in range from 0.02 to 0.1 mass%. At this the values of Tg and CP increase and b coefficient decrease with increasing content of fullerene. Concentration dependence of CP and b values is less steep for polymer composite films in elastic state at temperatures above Tg. Molecular interactions in t...

Effect of fullerene on the radical homo- and copolymerization of N-vinylpyrrolidone and (Di)methacrylates

The effect of fullerene on the kinetics of homopolymerization of N-vinylpyrrolidone and its copolymerization with methyl methacrylate and triethylene glycol dimethacrylate is studied via absorption spectroscopy and isothermal calorimetry. It is shown that the addition of fullerene brings about the inhibition of polymerization. The duration of the induction period becomes shorter when small amounts of methacrylic mono- and bifunctional monomers or a chain-transfer agent are added to N-vinylpyrrolidone. The resulting polymers are characterized by IR and absorption spectroscopy.

Atomic force microscopy of the supramolecular organization and strength properties of ultrathin polysiloxane block copolymer films

Ultrathin films of polysiloxane block copolymers and their composites with modifying additives of the C60 fullerene have been studied using atomic force microscopy. It has been revealed that, independently of the concentration of the additives, the surface relief of the films has an ordered structure with a period of approximately 35 nm, which is associated with the presence of a spatial network of rigid block domains of ladder phenylsilasesquioxane in the block copolymer. The mechanical properties of the films have been determined from indentation tests of their surface layers. Reliable quantitative measurements have been performed with specially fabricated spherical indenters of the calibrated submicron radius of curvature. The obtained values of the strength parameters correlate with the data derived from standard physical and mechanical tests of thick films. It has been found that the addition of the C60 fullerene at a level of 0.01% significantly improves the elasticity of the surface layers of the block copolymer.

Effect of fullerene black additions on the tribological properties of armamid PA SV30-1

The tribological properties of Armamid PA SV30-1 material with additions of fullerene black were studied using LZ-TsNII(U) plastic lubricant.

Figure of merit enhancement in bismuth telluride alloys via fullerene-assisted microstructural refinement

Nanocomposite materials based on bismuth telluride with fullerene additions have been synthesized via ball milling and spark plasma sintering. The impact of fullerene addition upon the composites is studied with respect to both fullerene volume percentage and ball-mill duration. It is demonstrated that fullerenes can engage in significant microstructural refinement even when present in small quantities. The lattice thermal conductivity, electrical conductivity, Seebeck coefficient, and Hall coefficient are analyzed with a view to the impact of fullerene incorporation upon these properties. Fullerene-assisted microstructural refinement causes a decrease both in lattice thermal conductivity and electrical conductivity, but a corresponding increase in the Seebeck coefficient results in an enhancement in the figure of merit at low volume fractions.

Effect of C60 fullerene additions on the thermal conductivity of low-density polyethylene films

The thermal conductivity of LDPE + C60 nanocomposites with a fullerene concentration up to 10 wt % is studied in the temperature range 20–80°C. This conductivity is found to nonlinearly decrease with increasing fullerene concentration. The decrease in the thermal conductivity of the composites is considered to be caused by a decrease in the phonon mean free path as a result of an increase in the number of scattering centers. The temperature dependence of the thermal conductivity is found to have a maximum.

Mn4-hinged bithiacalix[4]arenes accommodating fullerenes

The calixarene-Mn(4)-calixarene dumbbell-like unit can accommodate different fullerenes with its changeable curved surfaces and the addition of fullerenes completely remodels the packing of the dumbbell units.

Thermodynamics of TMPC/PSd/Fullerene Nanocomposites: SANS Study

We report a small angle neutron scattering study of the thermodynamics of a polymer mixture in the presence of nanoparticles, both in equilibrium and during phase separation. Neutron cloud point measurements and random phase approximation (RPA) analysis demonstrate that 1−2 mass % of C60 fullerenes destabilizes a highly interacting mixture of poly(tetramethyl bisphenol A polycarbonate) and deuterated polystyrene (TMPC/PSd). We unequivocally corroborate these findings with time-resolved temperature jump experiments that, in identical conditions, result in phase separation for the nanocomposite and stability for the neat polymer mixture. At lower C60 loadings (viz. 0.2−0.5 mass %), stabilization of the mixture is observed. The nonmonotonic variation of the spinodal temperature with fullerene addition suggests a competitive interplay of asymmetric component interactions and nanoparticle dispersion. The stability line shift depends critically on particle dispersion and vanishes upon nanoparticle agglomeration.

Specific Features of the Distribution of Modifying Fullerene Additives in Ultrathin Polymeric Films

Nanocomposites of polyblock polysiloxane copolymers and fullerenes by the method of small-angle neutron scattering are investigated. It was shown that a uniform distribution of threshold additive of fullerenes in ultrathin polymeric films is possible. The main results of the investigation involve: (1) in the range of radiuses below 70 nm in the films there are observed scattering structures with radiuses ∼5 nm, ∼35 nm, and ∼60 nm; (2) in the sample free of fullerene, structures of radius ∼60 nm are not detected; (3) structures of radius 60 nm appear only in the samples, which contain fullerenes, therewith their part grows with the increase of the fullerenes content. In the work was suggested, that the critical role in formation C60 clusters is played by the supramolecular organization of the initial block.

Fullerene–epoxy nanocomposites-enhanced mechanical properties at low nanofiller loading

In this study, we characterized the mechanical properties of fullerence (C60) epoxy nanocomposites at various weight fractions of fullerene additives in the epoxy matrix. The mechanical properties measured were the Young’s modulus, ultimate tensile strength, fracture toughness, fracture energy, and the material’s resistance to fatigue crack propagation. All of the above properties of the epoxy polymer were significantly enhanced by the fullerene additives at relatively low nanofiller loading fractions (~0.1 to 1% of the epoxy matrix weight). By contrast, other forms of nanoparticle fillers such as silica, alumina, and titania nanoparticles require up to an order of magnitude higher weight fraction to achieve comparable enhancement in properties.

Tribological effects of fullerene (C60) nanoparticles added in mineral lubricants according to its viscosity

In this study, the tribological behaviors of fullerene nanoparticles-added mineral oil were investigated as a function of viscosities (e.g., 12, 30, 55, 96 and 145 mm2/s). Extreme pressure and anti-wear properties were evaluated using a four-ball tester, respectively. The lubrication tests were performed with a disk-on-disk tester for different normal loads. Tribological properties were evaluated by measuring friction surface temperature and the friction coefficient, and interpreted in terms of the Stribeck curve. We note that the weld points of the raw- and nano-oil increased as the oil viscosity increased and weld points for all nano-oil were higher than those of raw oil. Also the wear scar diameters of the raw- and nano-oil decreased as the oil viscosity increased and wear scar diameters for all nano-oil were less than those of raw oil. Also, we have found that the difference of friction coefficient between raw oil and nano-oil was outstanding when the viscosity of raw oil was low and the normal load is high. Our results indicate that the addition of fullerene additives in lubricant was more effective when the viscosity of raw oil was low under the higher normal load conditions.

Regioselectivity in Tether‐Directed Remote Functionalization – The Addition of a Cyclotriveratrylene‐Based Trimalonate to C60 Revisited

AbstractThe Bingel addition of a trimalonate derived from a chiral, cyclotriveratrylene (CTV)‐based tripodal tether to C60 was reinvestigated. The present use of enantiomerically pure (P)‐ and (M)‐configured CTV units in the tether allowed the isolation of a total of four enantiomerically pure C3‐symmetric tris‐adducts of [60]fullerene (two from each CTV enantiomer). With the support of NMR and UV/Vis spectroscopy, electronic (ECD) and vibrational (VCD) circular dichroism spectroscopic analysis (comparison to ECD data of known compounds and to ECD and VCD data calculated by TD‐DFT or ZINDO methods as part of this work) allowed a definitive determination of the following structural features for all four CTV‐C60 conjugates: (i) The constitution of the fullerene addition pattern, (ii) its absolute configuration, and (iii) the absolute configuration of the CTV moiety. It is concluded that the triple Bingel addition proceeded with complete regioselectivity and negligible diastereoselectivity, affording only the trans‐3,trans‐3,trans‐3 fullerene addition pattern in both enantiomeric forms, whereas the previously reported e,e,e motif was not formed.