Experimental Study and Numerical Modeling of Rheological and Flow Behavior of Xanthan Gum Solutions Using Artificial Neural Network

This study investigated effect of temperature, concentration, and shear rate on rheological properties of xanthan gum aqueous solutions using a Couette viscometer at temperatures between 25°C and 55°C and concentrations of 0.25 wt% to 1.0 wt%. The Herschel–Bulkley model described very well the non-Newtonian behavior of xanthan gum solutions. Shear rate, temperature, and concentration affected apparent viscosity and an equation was proposed for the temperature and concentration effect valid for each shear rate. This article also presents an artificial neural network (ANN) model to predict apparent viscosity. Based on statistical analysis, the ANN method estimated viscosity with high accuracy and low error.     

Designing syntheses of cellulose and starch derivatives with basic or cationic N‐functions: part I—cellulose derivatives

The use of cellulose and starch derivatives that bear amino or quaternary ammonium moieties is steadily increasing, and the applications in industry are continuing to grow. These promising products are routinely used in cosmetic and paper‐making industries. This article provides an overview of strategies available to chemists for designing the syntheses of such compounds. The review provides a brief historical perspective on synthesis and describes recent developments that have enabled chemists to enhance their synthesis productivity. However, the graft polymerization techniques are far from the scope of this paper and will be noted in a few words only. In addition to the structural and synthetic aspects, applications of these derivatives are discussed in brief. We have divided this article in two parts mainly because of the vastness of the subject and limited space available. The first part of which reviews the advances in the synthesis of basic and cationic cellulose derivatives having amino or quaternary ammonium moieties and the second part of which considers starch ones. Copyright © 2015 John Wiley & Sons, Ltd.     

Facile Biogenic Synthesis and Characterization of Seven Metal-Based Nanoparticles Conjugated with Phytochemical Bioactives Using Fragaria ananassa Leaf Extract

In this investigation, for the first time, we used Fragaria ananassa (strawberry) leaf extract as a source of natural reducing, capping or stabilizing agents to develop an eco-friendly, cost-effective and safe process for the biosynthesis of metal-based nanoparticles including silver, copper, iron, zinc and magnesium oxide. Calcinated and non-calcinated zinc oxide nanoparticles also synthesized during a method different from our previous study. To confirm the successful formation of nanoparticles, different characterization techniques applied. UV-Vis spectroscopy, X-ray Diffraction (XRD) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), Photon Cross-Correlation Spectroscopy (PCCS) and Fourier Transformed Infrared Spectroscopy (FT-IR) were used to study the unique structure and properties of biosynthesized nanoparticles. The results show the successful formation of metal-based particles in the range of nanometer, confirmed by different characterization techniques. Finally, the presented approach has been demonstrated to be effective in the biosynthesis of metal and metal oxide nanoparticles.     

Thermal,combustion and optical properties of new polyimide/ODA-functionalized Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanocomposites containing xanthene and amide groups

Polypropylene (PP), due to its chemical stability, is considered one of the main responsible of the increasing amount of plastic wastes on earth. To overcome this problem and to reduce the dependence of oil feedstocks, the use of lignocellulosics as fillers or reinforcements in thermoplastic materials has been increasing enormously in the last decades. In the present work, Liquid Wood (a mixture of cellulose, hemp, fax and lignin) was used to prepare, by mechanical mixing followed by thermal extrusion, blends of various PP/Liquid Wood ratios. Differential scanning calorimetry and thermogravimetric analysis experiments were performed in order to verify whether and how much the composition of the blends affects the thermal properties of the obtained compounds. Both calorimetric and thermogravimetric results indicate that the application of PP as a matrix does not limit the processing temperature of Liquid Wood, which may lead to a perfect marketable composite from these components. The addition of Liquid Wood also resulted in enhanced mechanical properties for the PP/Liquid Wood blends.     

Microwave-assisted efficient synthesis of azlactone derivatives using TsCl/DMF under solvent-free conditions

A simple and efficient procedure for the synthesis of azlactones employing condensation reaction of aromatic aldehydes with hippuric acid has been developed by using the tosyl chloride (TsCl) and dimethylformamide (DMF) system as condensing agent in the absence of solvents under microwave irradiation. The present protocol is operationally simple and offers several advantages such as high yields, short reaction time, and simple workup.     

Polymerization of ethylene using a series of binuclear and a mononuclear Ni (II)‐based catalysts

A novel series of homo‐, bi‐, and mononuclear Ni(II)‐based catalysts (BNC_n n = 1–4, MNC₄) were used for ethylene polymerization. The optimum conditions for the catalyst BNC₄ (the highest catalytic activity) was obtained at [Al]/[Ni]=2000/1, T_p = 42 °C, and t_p = 20 min that was 1073 g PE/mmol Ni h. In theoretical study, steric and electronic effects of substituents and diimine backbone led to prominent influence on the catalyst behavior. The highest M_V was resulted from polymerization using BNC₄; however, the highest unsaturation content was obtained from BNC₁. GPC analysis showed a broad MWD (PDI = 17.8). BNC₁ and BNC₂ in similar structures showed broad peaks in DSC thermogram, while BNC₃ and BNC₄ with more electronic effects showed a peak along with a wide shoulder. Monomer pressure increasing showed enhancing in activity of the BNC₄, meanwhile a peak with shoulder to a single peak in DSC thermogram and uniformity in morphology of the resulted polymer were observed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3000–3011     

Synthesis and characterization of new optically active and organosoluble poly(ester-imide)s based on bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide by direct polycondensation

New optically active poly(ester-imide)s PEIs were prepared from newly synthesized N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-L-isoleucine diacid 4 via direct polycondensation with various aromatic diols in a system of tosyl chloride (TsCl), pyridine (Py), and N,N-dimethylformamide (DMF). The reactions with bicyclo TsCl were significantly promoted by controlling alcoholysis with diols, in the presence of catalytic amounts of DMF, to give a series of optically active PEIs, with good yield and ...