Synthesis,characterization, and thermal degradation of novel poly(2‐(5‐bromo benzofuran‐2‐yl)‐2‐oxoethyl methacrylate)

A novel methacrylate monomer containing benzofuran side group, 2‐(5‐bromo benzofuran‐2‐yl)‐2‐oxoethyl methacrylate (BOEMA), was synthesized from esterification reaction of 2‐bromo‐1‐(5‐bromo benzofuran‐2‐yl) ethanone with sodium methacrylate at 85°C in the presence of 1,4‐dioxane solvent. After characterization with Fourier transform infrared spectrophotometer, nuclear magnetic resonance (¹H‐NMR and ¹³C‐NMR), its homopolymerization was carried out by free radical polymerization at 60°C in the presence of benzoyl peroxide initiator and 1,4‐dioxane solvent. The glass transition temperature (T_g) of the synthesized novel polymer, poly(2‐(5‐bromo benzofuran‐2‐yl)‐2‐oxoethyl methacrylate) [poly(BOEMA)], was determined to be 137°C with differential scanning calorimetry technique. Thermal degradation kinetics of poly(BOEMA) was investigated by thermogravimetric analysis method at different heating rates with 5°C/min intervals between measurements. From dynamic measurements, the analysis of each process mechanism of Coats–Redfern and Van Krevelen methods showed that the most probable model for the decomposition process of poly(BOEMA) homopolymer agrees with the random nucleation, F₁ mechanism. The apparent decomposition activation energies of poly(BOEMA) by Kissinger's and Flynn–Wall–Ozawa methods in the studied conversion range were 188.47 and 180.13 kJ/mol, respectively. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

A new approach for data stream classification: unsupervised feature representational online sequential extreme learning machine

Multimedia Tools and Applications - The characteristics of the data stream have brought enormous challenges to classification algorithms. Concept drift is the most concerning characteristics, and...     

Electrical charge transport and optical properties of a poly(methacrylate) with a new side chain and its Ni(II) complex

The electronic conductivity of poly[2‐(2‐hydroxybenzyliden hydrazino)thiazole‐4‐yl methyl methacrylate] bearing a thiazole ring, Schiff base, and hydroxyl group in its side chain and its Ni(II) complex were measured as functions of temperature and frequency. The electrical measurements show the semiconducting nature of the samples as their electrical conductivity increased with increased temperature. Also, the activation energies were below 2 eV, which places them in the semiconductor regime. The conduction mechanism in the samples is discussed. Although extrinsic conduction mechanism occurs in the polymer, intrinsic conduction mechanism take places in its metal complex. The optical absorption spectra were recorded at room temperature and the optical energy gaps of samples were determined by optical spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 741–746, 2003     

Metal-containing Polymers Synthesized via Acyclic Diene Metathesis (ADMET) Polymerization Using Electrochemically-Reduced Tungsten-based Catalyst: Polycarbosilanes

Acyclic diene metathesis (ADMET) polymerization of dienes containing silicon using electrochemically produced active catalyst species (WCl₆-e⁻-Al-CH₂Cl₂) was investigated. Silicon-containing unsaturated polymers were characterized by ¹H- and ¹³C-NMR spectroscopy, gel permeation chromatography (GPC) and elemental analysis. The thermal behavior of the polymers was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).     

Development of novel pea flour‐based nanofibres by electrospinning method

The aim of this study was to produce pea flour and hydroxypropyl methylcellulose (HPMC)‐based novel nanofibres using electrospinning method. The effects of pH, pea flour and HPMC concentration on apparent viscosity, electrical conductivity of electrospinning solutions and nanofibre characteristics were studied. Solutions were prepared at different pH values (7, 10, 12), with different pea flour concentrations (1%, 2% w/v) and HPMC concentrations (0.25%, 0.5%, 1.0% w/v). For all pea flour concentrations, k values increased significantly with increase in pH and HPMC concentration. It also increased with increase in pea flour concentration for basic solutions. Pea flour concentration increased diameter and water vapour permeability (WVP) values of nanofibres. This study showed that electrospinning was a promising method for fabrication of homogenous pea flour and HPMC‐based nanofibres to be used in packaging industry.     

Buckling of symmetric cross-ply square plates with various boundary conditions

The buckling analysis of cross-ply laminated square plates subjected to three types of in-plane forces and various edge boundary conditions is presented on the basis of a unified five-degree-of-freedom shear deformable plate theory. The employment of the appropriate “shear deformation shape functions” in the theory leads to certain shear deformable plate theories developed previously, also, fulfills the requirement of the continuity conditions among the layers. The governing equations of buckling behaviour of completely simply supported cross-ply laminated plates are solved analytically. For the plates with different combinations of free, clamped and simply supported boundary conditions at their edges, the Ritz method is applied by assuming the displacement components as the double series of simple algebraic polynomials. The numerical results obtained on the basis of various plate theories for uniaxial, biaxial compression and compression–tension types of loading and different length-to-thickness ratios are presented and compared with the ones available in the literature.     

In-situ Single Chamber Arc Sputtering Process for Ycd0.3Ba2Cu3O7-δ Superconducting Thin Films

Superconducting YCd _0.3 Ba ₂ Cu ₃ O _7- thin films have been deposited in-situ onto single crystal MgO substrates using a DC arc-sputtering process. The depositions were carried out in a single chamber deposition system equipped with two target holders. The films deposited at the optimum condition exhibited strong (00l) orientation with a high peak intensity. The best electrical properties were achieved to be 90K for T _c , 81K for T _zero and the transport critical current density J _c =675 A/ cm ² at 77K and 2.3×10 ³ A/cm ² at 4.2K for the sample deposited at the optimum conditions.     

Novel Making of Bacterial Cellulose Blended Polymeric Fiber Bandages

Bacterial cellulose (BC) is a very promising biological material. However, at present its utilization is limited by difficulties in shape forming it. In this Communication, it is shown how this can be overcome by blending it with poly(methylmethacrylate) (PMMA) polymer. BC:PMMA fibers are produced by pressurized gyration of blended BC:PMMA solutions. Subsequently, BC:PMMA bandage‐like scaffolds are generated with different blends. The products are investigated to determine their morphological and chemical features. Cell culture and proliferation tests are performed to obtain information on biocompatibility of the scaffolds.