Chemistry

Processability and Characterization of Poly(Vinyl Chloride)-B-Poly(N-Butyl Acrylate)-B-Poly(Vinyl Chloride) Prepared by Living Radical Polymerization of Vinyl Chloride. Comparison With a Flexible Commercial Resin Formulation Prepared With PVC and Dioctyl Phthalate

G.Maria , C.Jorge , P.Anatoliy , G.Pedro , C.Mafalda


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This work reports the synthesis and processing of a new flexible material based on PVC produced by living radical polymerization. The synthesis was carried out in a two-step process. In the first step the macroinitiator alpha, omega-di(iodo)poly(butyl acrylate) [alpha, omega-di(iodo)PBA] was synthesized in water by single electron transfer/degenerative chain transfer mediated living radical polymerization (SET-DTLRP) catalyzed by Na2S2O4. In the second step this macroinitiator was reinitiated by SET-DTLRP of vinyl chloride (VC), thereby leading to the formation of the block copolymer poly(vinyl chloride)-b-poly(butyl acrylate)-b-poly(vinyl chloride) [PVC-b-PBA-b-PVC]. This new material was processed on a laboratory scale. The DMTA traces showed only a single glass transition temperature, thus indicating that no phase segregation was present. The copolymers were studied with regard to their processing, miscibility, and mechanical properties. The first comparison with commercial formulations made with PVC and dioctyl phthalate (DOP) is presented. J. VINYL ADDIT. TECHNOL., 12:156-165, 2006. © 2006 Society of Plastics Engineershttp://dx.doi.org/10.1002/vnl.2008

Oriented gold nanorods and gold nanorod chains within smectic liquid crystal topological defects

B.Gallas , F.Charra , E.Lacaze , C.Fiorini-Debuisschert , V.Dupuis , J.Fresnais , B.Rozic , C.Molinaro , J.Calixte , S.Umadevi , S.Lau-Truong , N.Felidj , T.Kraus , T.Hegmann


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We show that the use of oriented linear arrays of smectic A defects, the so-called smectic oily streaks, enables the orientation of gold nanorods for a large range of GNR diameters, ranging from 7 to 48 nm, and for various ligands. For the small GNRs it enables oriented end-to-end small chains of GNRs when the density is increased from around 2 GNRs/m2 to around 6 GNRs/m2. We have characterized the orientation of single GNRs by spectrophotometry and two-photon luminescence. A strongly anisotropic absorption of the composites and an onoff switching of GNR luminescence, both controlled by incident light polarization, are observed, revealing an orientation of the GNRs mostly parallel to the oily streaks. A more favorable trapping of GNRs by smectic dislocations with respect to ribbon-like defects is thus demonstrated. The dislocations appear to be localized at a specific localization, namely, the summit of rotating grain boundaries. Combining plasmonic absorption measurements, TPL measurements, and simulation of the plasmonic absorption, we show that the end-to-end GNR chains are both dimers and trimers, all parallel to each other, with a small gap between the coupled GNRs, on the order of 1. 5 nm, thus associated with a large red-shift of 110 nm of the longitudinal plasmonic mode. A motion of the GNRs along the dislocations appears as a necessary ingredient for the formation of end-to-end GNR chains, the gap value being driven by the balance between the attracting van der Waals interactions and the steric repulsion between the GNRs and leading to interdigitation of the neighboring ligands. We thus obtain electromagnetic coupling of nanorods controlled by light polarization.

Chlorination of RuO2 With Gaseous Cl2 Between 998 and 1123 K

B.Ana , G.Cristina , d.Micco,


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Employing methods of separation based on selective chlorination it is possible to separate valuable components, such as metals and rare earths, from ores and / or solid wastes. In this paper we study the chlorination reaction of ruthenium oxide. This element is among nuclear fission products, also part of many electronic wastes and numerous catalysts in the chemical industry. The study of the chlorination reaction of ruthenium oxide will allow to analyze in which conditions it is possible to apply gaseous chlorination for ruthenium recovery. No systematic studies on the kinetics and chemical mechanism of ruthenium oxide chlorination are available in the literature. In the present study, we performed a thermodynamic analysis of possible reaction pathways. The reaction products were identified by scanning electron microscopy (SEM) and x-ray Diffraction (xrd), and the experimental conditions for obtaining stable α-RuCl3 by RuO2 chlorination and subsequent heating in Cl2 were established. The starting temperature for the chlorination was determined at 983 K. The observed mass loss is due to formation of volatile products. We analyzed the effects of gas flow rate, crucible geometry, and sample mass on the kinetics of the reaction, in order to establish the corresponding experimental reaction conditions for chemical kinetic control. The effect of temperature was analyzed and an apparent activation energy of 173 ± 8 kJ.mol-1 was obtained for the chlorination reaction.Fil: Bohe, Ana Ester. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche; Argentina. Comision Nacional de Energia Atomica. Gerencia Complejo Tecnologico Pilcaniyeu; ArgentinaFil: Guibaldo, Cristina Noemi. Comisión Nacional de Energía Atómica; ArgentinaFil: de Micco, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica. Gerencia Complejo Tecnologico Pilcaniyeu. Division Cinetica Quimica; Argentin

Characterization of physical, thermal and spectral properties of biofield treated 2,6-dichlorophenol

M.Kumar , A.Branton , D.Trivedi , G.Nayak , S.Jana , R.Mohan , R.Mishra


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2,6-Dichlorophenol is a compound used for the synthesis of chemicals and pharmaceutical agents. The present work is intended to evaluate the impact of Mr. Trivedis biofield energy treatment on physical, thermal and spectral properties of the 2,6-DCP. The control and treated 2,6-DCP were characterized by various analytical techniques such as X-ray diffraction , differential scanning calorimetry , thermogravimetric analysis , Fourier transform infrared spectroscopy, and ultra violet-visible spectroscopy analysis. The XRD results showed the increase in crystallite size of treated sample by 28. 94% as compared to the control sample. However, the intensity of the XRD peaks of treated 2,6-DCP were diminished as compared to the control sample. The DTA analysis showed a slight increase in melting temperature of the treated sample. Although, the latent heat of fusion of the treated 2,6-DCP was changed substantially by 28% with respect to the control sample. The maximum thermal decomposition temperature of the treated 2,6-DCP was decreased slightly in comparison with the control. The FT-IR analysis showed a shift in C=C stretching peak from 14641473 cm-1in the treated sample as compared to the control sample. However, the UV-vis analysis showed no changes in absorption peaks of treated 2,6-DCP with respect to the control sample. Overall, the result showed a significant effect of biofield energy treatment on the physical, thermal and spectral properties of 2,6-DCP. It is assumed that increase in crystallite size and melting temperature of the biofield energy treated 2,6-DCP could alleviate its reaction rate that might be a good prospect for the synthesis of pharmaceutical compounds.
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