Study of stabilization of self-assembly processes in fullerene C60 solution

The dynamics of changes in the values of the refractive index of solutions of C60 in xylene at various concentrations has been studied by the refractometric method. It was found that the deviation from the linear form of the dependence of the refractive index on the C60 concentration occurs at a C60 concentration of 1.8 mg/ml. The deviation is associated with the largest number of molecular interactions between C60−C60 and the formation of large nanoclusters on their basis in solution. It was found by the dynamic light scattering (DLS) that the final size of C60 nanoclusters in solution depends on the initial concentration of the solute. A higher initial concentration of C60 leads to the synthesis of nanoclusters with a larger diameter. Using the method of optical spectroscopy, the processes of self-organization of fullerene C60 molecules in a xylene solution in time are studied. The character of stability of synthesized fullerene nanoclusters in solution is discussed. The results obtained are of particular importance for numerous applications of nanotechnology for understanding self-assembly processes and the development of new nanomaterials.

Mechanical and morphology characteristics of natural rubber-styrene butadiene rubber (NR-SBR) blends in the presence of natural microbentonite

Natural rubber (NR) has been the world renewable natural elastomer produced mainly in South East Asia from the sap of rubber tree (hevea brasiliensis). However it only exported to manufacturing countries for production of various engineering and specialty rubber products. Blending of the natural rubber with synthetic rubber such as styrene butadiene rubber (SBR) is a mean to improve engineering specification of the NR, especially due to exposure of mineral oils during its service life. Whereas natural microbentonite functions not only as filler but also as coagulant breaker in both SIR-10 and SBR matrices, which improves miscibility of the blends. In this work blending of Indonesian natural rubber (NR: SIR-10) with styrene butadiene rubber (SBR) were carried out in reflux reactor in xylene solution in the presence of various loading of natural microbentonite as fillers. Miscibility of the blends were measured from their mechanical properties as well as morphology of their fracture surfaces using electron microscopy (SEM). It was found that optimum loading of microbentonite in the NR/SBR (weight ratio: 50/50) blend was 3 per hundred rubber (phr), which showed good adhesion of the rubber matrices onto the filler surface and without any agglomeration.

MODIFICATION OF COPOLYMERS BASED ON OLEFIN AND MALEIC ANHYDRIDE AS POUR POINT DEPRESSANT FOR WAXY OILS

In this work, we investigated a modification of a copolymer based on α-olefin (octadecene-1) (ODC) and maleic anhydride (MA) synthesized by the method of initiated radical polymerization. In the studies carried out, it was revealed that of all the synthesized copolymers based on maleic anhydride, the copolymer with α-octadecene was the most effective copolymer in reducing the viscosity of oil and TPT. In this work, a copolymer based on maleic anhydride and octadecene-1 (ODC – MA) was modified with primary amines – butylamine (BA), hexylamine (HA), hexadecylamine (HDA), octadecylamine (ODA), benzylamine (BzA). The copolymer was modified in a xylene solution with a Dean – Stark packing; the ratio of the ODC – MA copolymer to amines was 1:1.2 mol. Tololsulfonic acid (TSC) 0.5 wt% was used as a catalyst. Synthesis temperature 140°C, time 8 hours. The degree of completion of the reaction was evaluated by the amount of water formed in the Dean Stark packing. Modified copolymers ODC – MA with amines (ODC – MA – BA, ODC – MA – HA, ODC – MA – HDA, ODC – MA – ODA, ODC – MA – BzA) were characterized by Fourier IR spectroscopy and 1H and 13C NMR spectroscopy, which indicates the transformation of the original anhydride rings into imide ones. Modified copolymers were tested on waxy oil as depressants. Moreover, all modified copolymers exhibit the properties of depressants – they reduce the viscosity and TPT of oil relative to oil without an PPD. The morphology of waxy crystals formed in oil during a decrease in temperature was determined by microscopy; it was shown that modified waxy crystals of small sizes are formed compared to the original oil without PPDs, which indicates the dispersing effect of modified copolymers based on ODC – MA.

A solid-liquid two-phase precipitation method for growth of fullerene (C60) nanowires

A novel solid-liquid two-phase precipitation (SLTPP) method, utilising a solidified (via liquid N2) m-xylene solution of C60 with liquid isopropanol (IPA) as the counter-solvent, is proposed for the synthesis of...

ENHANCEMENT OF THE SURFACE DIELECTRIC AND PHOTODIELECTRIC PROPERTIES OF LOW DENSITY POLYETHYLENE BY ADDING EMODIN

In this paper, we report surface dielectric and photodielectric properties of low density polyethylene (LDPE)/Emodin composite. Emodin was extracted from Fallopia japonica plant. The composite was obtained from the xylene solution. Dielectric measurements were performed in the frequency range from 240 Hz to 4 kHz and the temperature range from 20 °C – 70 °C. Irradiations of the sample were applied before and during measurement with selected wavelengths from UV to the visible range. Surface dielectric conductance and susceptance of the LDPE/Emodin composite is higher then value of conductance and susceptance of pure LDPE. We found an increase, by one order of magnitude, in conductance and susceptance of the LDPE/Emodin composite with increase of measurement frequency. Furthermore, the surface conductance and susceptance increase due to UV radiation in mentioned temperature range, but during visible radiation at frequency 1 kHz (except in the case green LED lamp) we observed the enhance of conductance only at temperature range up to 50 °C.

3H-1,2-Benzodithiole-3-thione

The almost planar (r.m.s. deviation = 0.034 Å) title compound, C7H4S3, was synthesized by reacting 2,2-dithiodibenzoic acid with phosphorus pentasulfide in xylene solution. In the crystal, short S...S [3.3727 (14), 3.3765 (13) and 3.4284 (13) Å] contacts and aromatic π–π stacking [shortest centroid–centroid separation = 3.618 (2) Å] are observed.

Preparation of graphene and inclusion in composites with poly(styrene-b-butadiene-b-styrene)

The aim of this work was to prepare and characterize nanocomposites containing graphene from intercalated graphite. The graphene was produced by rapid thermal expansion using expandable graphite oxide or obtained commercially. The polymer used was poly(styrene-b-butadiene-b-styrene) (SBS). The SBS was dissolved in p-xylene and the graphene was ultrasonically suspended in the xylene solution. The morphology, dynamic mechanical, electrical, and thermal properties of composites were characterized. Graphene at 1% (w/w) (hydrogen atmosphere) was found to increase the storage modulus (68%) and loss modulus (147%) of the glassy state of polybutadiene in SBS. The damping factor of SBS was enhanced by 74% corresponding to the polystyrene phase of SBS using Cheap Tubes graphene. The composites were insulators at 1% (w/w). The styrene groups in SBS strongly adsorb onto the graphenes, preventing a percolation network that would enhance electrical permittivity. Graphene enhanced physical crosslinks of the polystyrene phase to increase the modulus at low concentration. Graphene dispersion using ultrasonic shear depended on π-π interactions between the aromatic rings of the solvent, graphene, and polystyrene. This is a simple, fast, cheap, and scalable way of making high-quality graphene and a new way of graphene dispersal in polymers.

Morphology and Microstructure of Aggregates and Gelation Behaviour of Poly(3-hexylthiophene) in Xylene Solution

In this work, we investigate the morphology and microstructure of the aggregates, and the gelation behaviour of Poly(3-hexylthiophene) (P3HT) conjugated polymer in xylene solution as functions of P3HT concentration and aging time by the means of ageing time test, wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), UV-visible absorption (UV-vis) and photoluminescence (PL) spectra. The result reveals that the gelation time of P3HT/xylene solution decreases markedly with increasing P3HT concentration. The photophysical properties of the P3HT aggregates in P3HT/xylene solution increase as P3HT concentration and ageing time are raised. It indicates that the well soluble P3HT polymer chains in xylene solution present microphase separation and self-assemble into stiff sheetlike structure, which associates by rodlike nanowhiskers of P3HT polymers during aging. Upon prolonged aging, the sheetlike structure of P3HT aggregates to from the three-dimension network that improves the electronic particle mobility in the organic solar cell.