Conventional radical polymerization and iodine‐transfer polymerization of 4′‐nonafluorobutyl styrene: Surface and thermal characterizations of the resulting poly(fluorostyrene)s

4′‐Nonafluorobutylstyrene (3) was synthesized and polymerized by conventional and controlled radical polymerization (iodine transfer polymerization (ITP)). Such an aromatic fluoromonomer was prepared from Ullmann coupling between 1‐iodoperfluorobutane and 4‐bromoacetophenone followed by a reduction and a dehydration in 50% overall yield. Two radical polymerizations of (3) were initiated by AIBN either under conventional or controlled conditions, with 1‐iodoperfluorohexane in 84% monomer conversion and in 50% yield. ITP of (3) featured a fast monomer conversion and a linear evolution of the ln([M]₀/[M]) versus time. The kinetics of radical homopolymerization of (3) enabled one to assess its square of the propagation rate to the termination rate (k_p²/k_t) in ITP conditions (36.2·10^?2 l·mol^?2·sec^?2 at 80 °C) from the Tobolsky's kinetic law. Polydispersity index (?) of the fluoropolymer achieved by conventional polymerization was 1.30 while it worthed 1.15 when synthesized by ITP. Thermal stabilities of these oligomers were satisfactory (10% weight loss under air occurred from 305 °C) whereas the melting point was 47 °C. Contact angles and surface energies assessed from spin‐coated poly(3) films obtained by conventional (hysteresis = 18°, surface energy 18 mN.m^?1) and ITP (hysteresis = 47°, surface energy 15 mN.m^?1) evidenced ? values' influence onto surface properties of the synthesized polymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3202–3212     

Recent developments in microbial inulinases

Microbial inulinases are an important class of industrial enzymes that have gained much attention recently. Inulinases can be produced by a host of microorganisms, including fungi, yeast, and bacteria. Among them, however, Aspergillus sp. (filamentous fungus) and Kluyveromyces sp. (diploid yeast) are apparently the preferred choices for commercial applications. Among various substrates (carbon source) employed for their production, inulin-containing plant materials offer advantages in comparison to pure substrates. Although submerged fermentation has been universally used as the technique of fermentation, attempts are being made to develop solidstate fermentation technology also. Inulinases catalyze the hydrolysis of inulin to d-fructose (fructose syrup), which has gained an important place in human diets today. In addition, inulinases are finding other newer applications. This article reviews more recent developments, especially those made in the past decade, on microbial inulinases—its production using various microorganisms and substrates. It also describes the characteristics of various forms of inulinases produced as well as their applications.     

Raman visualization of micro- and nanoscale domain structures in lithium niobate

In this work we demonstrate the abilities of micro-Raman imaging in the study of ferroelectric domains and present its application to visualization of micro-scale periodical domain structures and nano-domains induced by laser irradiation in lithium niobate.     

Formation of simple organic molecules in the interstellar medium

In this work we present a methodology for the synthesis of simple molecules from basic formaldehyde (H₂CO) precursors. We have approached this challenging problem by considering a basic dimerization scheme that eventually leads to diose and methyl formate, using an HCO⁺ proton source. This species was chosen due to its ample abundance in the atmosphere. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008     

Entrepreneurs,Banks and the Monetary Circuit: A Single Period Investigation

Economic fluctuations constitute a serious problem for policy makers and economists. Several theories have been developed to explain their causes. New recent literature has emphasized the idea that the level of income and employment is determined by decisions taken jointly by banks and entrepreneurs. Our aim here is to investigate the increasingly important relationship between banks and entrepreneurs in the monetary circuit. The system considered explicitly models the money supply process, in contrast to the current economic literature, in which money is introduced ex post as an exogenous disturbance. In view of the presence of several parameters, the two-dimensional model is quite complex. A complete analysis of all possible outcomes of the ? -limit sets is performed, and the circumstances under which the system explodes, collapses or tends to an equilibrium are discussed in terms of the model parameters.     

Thermo-optic effects in electro-optic crystals used in an intensity-modulation system. – Application in LiTaO3

Linear electro-optic (EO) and thermo-optic (TO) effects are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point along the optical transmission curve of an EO-modulation system. In this framework, methods of EO measurements based on the frequency doubling appearing at the minimum-transmission point are formulated. Moreover, TO coefficients for various optical quantities, such as the refractive indices, n₀ and n_e, the spontaneous birefringence Δn⁽⁰⁾, the EO coefficient r, the half-wave voltage V_π, the optical phase retardation Γ, and the intensity modulation (IM) depth, m, are introduced and useful relationships between them are extracted. Also, applications of the above in the experimental field, with determinations of EO parameters and TO coefficients, are presented for the case of a congruent LiTaO₃ crystal. A comparison of the so-obtained experimental results with those derived from literature when a LiNbO₃ crystal is used demonstrates a number of advantages for the LiTaO₃-based system. PACS 78.20.Jq; 65.40.De     

Preparation and analysis of electronic-transport properties of BSCCO-2223 platelets

Il Nuovo Cimento D - High-quality single-phase thin platelets of BSCCO-2223 have been produced by a novel method on thermal-gradient-enhanced KCl flux which allows the growth of the 2223-phase in...     

Acetobacter cellulose pellicle as a temporary skin substitute

Applied Biochemistry and Biotechnology - A bacterial strain with morphological and biochemical properties close toAcetobacter xylinum has been cultured in nonagitated, inverted sucrose- and yeast...     

The viscous mucilage from the weedPortulaca oleracea,L

A polysaccharide complex has been extracted from the invasive and widespread weedPortulaca oleracea (purslane) in yields of up to 25 g% (dry wt). The clear and viscous mucilage displays physicochemical properties appropriate for industrial uses, such as food extenders and viscosifier. Toxic collateral effects can be precluded because of the already known uses in home remedies and animal feed. Anion exchange chromatography fractionated the crude complex into a neutral arabinogalactan and polydisperse pectin-like polysaccharides. This fractionation brings about a reduction in the viscosity observed for the native complex, whereas saponification ofO-acetyl and/or carboxy-methoxyl groups increases it.