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This paper describes the process of producing chemiresistors based on hybrid nanostructures obtained from graphene and conducting polymers. The technology of graphene presumed the following: dispersion and support stabilization based on the chemical vapor deposition technique; transfer of the graphene to the substrate by spin-coating of polymethyl methacrylate; and thermal treatment and electrochemical delamination. For the process at T = 950 °C, a better settlement of the grains was noticed, with the formation of layers predominantly characterized by peaks and not by depressions. The technology for obtaining hybrid nanostructures from graphene and conducting polymers was drop-casting, with solutions of Poly(3-hexylthiophene (P3HT) and Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). In the case of F8T2, compared to P3HT, a 10 times larger dimension of grain size and about 7 times larger distances between the peak clusters were noticed. To generate chemiresistors from graphene–polymer structures, an ink-jet printer was used, and the metallization was made with commercial copper ink for printed electronics, leading to a structure of a resistor with an active surface of about 1 cm2. Experimental calibration curves were plotted for both sensing structures, for a domain of CH4 of up to 1000 ppm concentration in air. A linearity of the curve for the low concentration of CH4 was noticed for the graphene structure with F8T2, presenting a sensitivity of about 6 times higher compared with the graphene structure with P3HT, which makes the sensing structure of graphene with F8T2 more feasible and reliable for the medical application of irritable bowel syndrome evaluation. [ABSTRACT FROM AUTHOR]

This paper describes the process to obtain ceramic nanotubes from titanium dioxide, alumina and yttrium oxide by a feasible, replicable and reliable technology, including three stages, starting from an electrospinning process of poly(methyl methacrylate) solutions. A minimum diameter of 0.3 μm was considered optimal for PMMA nanofibers in order to maintain the structural stability of covered fibers, which, after ceramic film deposition, leads to a fiber diameter of 0.5–0.6 μm. After a chemical and physical analysis of the stages of obtaining ceramic nanotubes, in all cases, uniform deposition of a ceramic film on PMMA fibers and, finally, a uniform structure of ceramic nanotubes were noted. The technological purpose was to use such nanotubes as ingredients in screen-printing inks for electrochemical sensors, because no study directly targeted the subject of ceramic nanotube applications for printed electronics to date. The printing technology was analyzed in terms of the ink deposition process, printed electrode roughness vs. type of ceramic nanotubes, derived inks, thermal curing of the electrodes and the conductivity of electrodes on different support (rigid and flexible) at different curing temperatures. The experimental inks containing ceramic nanotubes can be considered feasible for printed electronics, because they offer fast curing at low temperatures, reasonable conductivity vs. electrode length, good printability on both ceramic or plastic (flexible) supports and good adhesion to surface after curing. [ABSTRACT FROM AUTHOR]

Three new Metal-Organic Frameworks, containing mesitylene tribenzoic acid as a linker and zinc (1) or cadmium as metals (2,3), were synthesized through solvothermal reactions, using DMF/ethanol/water as solvents, at temperatures of 80 °C (structures 1 and 3) and 120 °C (structure 2). Following single-crystal X-ray diffraction, it was found that 1 and 3 crystallize in the P21/c and C2/c space groups and form 2D networks, while 2 crystallizes in the Fdd2 space group, forming a 3D network. All three frameworks, upon heating, were found to be stable up to 350 °C. N2 sorption isotherms revealed that 1 displays a BET area of 906 m2/g. Moreover, the porosity of this framework is still present after five cycles of sorption/desorption, with a reduction of 14% of the BET area, down to 784 m2/g, after the fifth cycle. The CO2 loading capacity of 1 was found to be 2.9 mmol/g at 0 °C. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of a two-dimensional Zn(II) coordination polymer employing a ligand with a biphenyl core containing imidazole and carboxylate groups in the presence of acetate moieties as bridging molecules. The obtained [ZnLAc]n was structurally characterized via X-ray, FTIR, TGA, PXRD, SEM and EDX analyses. Computer-aided calculations based on density functional theory (DFT) were employed to assess the optimal conformational geometries of both the starting ligand and the Zn(II) complex. Computational results were compared with the experimental data, disclosing a reasonable agreement. Comparisons between the single-crystal structures and the calculated optimized geometries of the molecular entities are discussed. In addition, the time-dependent DFT method (TD-DFT) was applied to assess the first excited state of the ligand and complex. [ABSTRACT FROM AUTHOR]

Abstract: Environmental proactivity is determined by several drivers, each of them being able to model the degree of corporate responses to environmental challenge. For more than twenty years Climate Change issues are still crossing both political and economic agenda. The increasing attention regarding environmental problems calls the company to react and adapt its strategy to this new issue. Despite the fact that in the next future the eco revolution would affect every business activity, there exist some industries with high environmental impact which more liable for such change. The aim of the paper is to present a fuzzy rule based model to assess a corporate environmental performance. In order to cope with this challenge the article illustrates an example from food industry. [Copyright &y& Elsevier]

This paper prepared composites under the free membranes form that are based on thermoplastic polymers of the type of polyurethane (TPU) and polyolefin (TPO), which are blended in the weight ratio of 2:1, and ceramic nanoparticles (CNs) such as BaSrTiO3 and SrTiO3. The structural, optical, and conductive properties of these new composite materials are reported. The X-ray diffraction studies highlight a cubic crystalline structure of these CNs. The main variations in the vibrational properties of the TPU:TPO blend induced by CNs consist of the following: (i) the increase in the intensity of the Raman line of 1616 cm−1; (ii) the down-shift of the IR band from 800 to 791 cm−1; (iii) the change of the ratio between the absorbance of IR bands localized in the spectral range 950–1200 cm−1; and (iv) the decrease in the absorbance of the IR band from 1221 cm−1. All these variations were correlated with a preferential adsorption of thermoplastic polymers on the CNs surface. A photoluminescence (PL) quenching process of thermoplastic polymers is demonstrated to occur in the presence of CNs. The anisotropic PL measurements have highlighted a change in the angle of the binding of the TPU:TPO blend, which varies from 23.7° to ≈49.3° and ≈53.4°, when the concentration of BaSrTiO3 and SrTiO3 CNs, respectively, is changed from 0 to 25 wt. %. Using dielectric spectroscopy, two mechanisms are invoked to take place in the case of the composites based on TPU:TPO blends and CNs, i.e., one regarding the type of the electrical conduction and another specifying the dielectric–dipolar relaxation processes. [ABSTRACT FROM AUTHOR]

2,4,6-Tris(4-iodophenyl)-1,3,5-trimethylbenzene was synthesized from 2,4,6-triphenyl-1,3,5-trimethylbenzene, using [bis(trifluoroacetoxy)iodo]benzene as the iodinating agent. The title compound was characterized by means of NMR, IR, and mass spectrometry, as well as TG analysis. [ABSTRACT FROM AUTHOR]