The Use of Recycled PET for the Synthesis of New Mechanically Improved PVP Composite Nanofibers.

Polyethylene terephthalate (PET) waste has become a major challenge for the conservation of the environment due to difficult degradation. For this reason, it is important to develop new recycling strategies for reusing this waste. In this work, the electrospinning technique was used to synthesize composite nanofibers of polyvinylpyrrolidone (PVP), recycling PET (RPET) that was obtained from the chemical recycling of postconsumer PET with glycolysis and styrene (ST) as a crosslinking agent. The polymer solutions were analyzed by viscosity and frequency sweeping, while the composite nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and nanoindentation to compare their properties. The PVP nanofibers presented an average diameter of 257 nm; the RPET/PVP and RPET/PVP/ST composite nanofibers had average diameters of 361 nm and 394 nm, respectively; and the modulus of elasticity and hardness of the RPET/PVP/ST composite nanofibers were 29 and 20 times larger, respectively, than those of the PVP nanofibers. With the synthesis of these composite nanofibers, a new approach to PET recycling is presented.

Sol-Gel PMMA-ZrO2 Hybrid Layers as Gate Dielectric for Low-Temperature ZnO-Based Thin-Film Transistors.

We report a simple sol-gel process for the deposition of poly(methyl methacrylate) (PMMA)-ZrO2 organic-inorganic hybrid films at low temperature and studied their properties as a function of the molar ratios of the precursors in the hybrid sol-gel solution, which included zirconium propoxide as the inorganic (zirconia) source, methyl methacrylate as the organic source, and 3-trimethoxy-silyl-propyl-methacrylate (TMSPM) as the coupling agent to enhance the compatibility between the organic and inorganic phases. The hybrid thin-film deposition was done on glass slide substrates by the dip-coating method. After deposition, the films were heat-treated at 100 °C for 24 h. The analysis of the hybrid films included Fourier transform infrared spectroscopy to identify their chemical groups and thermogravimetric analysis to determine the content of their organic and inorganic components. In addition, capacitance-voltage (C-V) and current-voltage (I-V) curves in metal-insulator-metal structures, using gold as metal contacts, were measured to find the dielectric constant and leakage current of the PMMA-ZrO2 hybrid films. Finally, because of their adequate dielectric characteristics, single hybrid layers were deposited on indium tin oxide-coated glass substrates and were tested as gate dielectric in thin-film transistors (TFTs), using sputtered ZnO layers as the semiconductor active channel. We measured the output electrical response and transfer characteristics of these hybrid dielectric gate-based devices and determined their main electrical parameters as a function of the TMSPM content in the hybrid dielectric gate layer. The better TFT electrical behavior presents field effect mobility of 0.48 cm2/V s, low threshold voltage of 3.3 V, and on/off current ratio of 105, and it was obtained by using PMMA-ZrO2 with 0.3 TMSPM content as the gate dielectric layer. The values obtained for the electrical parameters show that PMMA-ZrO2 hybrid films are quite suitable for dielectric gate applications in TFTs.

(1RS,2RS)-4,4'-(1-Aza-niumyl-2-hy-droxy-ethane-1,2-di-yl)dipyridinium tetra-chlorido-platinate(II) chloride.

The title compound, (C12H16N3O)[PtCl4]Cl, consists of a 4,4'-(1-aza-niumyl-2-hy-droxy-ethane-1,2-di-yl)dipyridinium trication, a square-planar tetra-chloridoplatinate(II) dianion and a chloride ion. In the cation, the pyridinium rings attached to the central 1-aza-niumyl-2-hy-droxy-ethane fragment have an anti conformation, as indicated by the central C-C-C-C torsion angle of -166.5 (6)°, and they are inclined to one another by 63.5 (4)°. In the crystal, the cations and anions are linked through N-H⋯Cl and O-H⋯Cl hydrogen bonds. There are also π-π contacts [centroid-centroid distances = 3.671 (4) and 3.851 (4) Å] and a number of C-H⋯Cl inter-actions present, consolidating the formation of a three-dimensional supra-molecular structure.