Characterization of Terebinth Fruit Oil and Optimization of Acidolysis Reaction with Caprylic and Stearic Acids

Characterization of the fatty acid and triacylglycerol composition of terebinth fruit oil and the synthesis of structured lipids (SL) were performed in this study. Interesterification reaction of terebinth fruits oil (Pistacia terebinthus L.) with caprylic acid (CA) and stearic acid (SA) to produce a SL was performed in n-hexane using immobilized sn-1,3 specific lipase from Mucor miehei. The effect of reaction conditions and relationship among them were analyzed by response surface methodology (RSM) with a four-factors five-level central composite rotatable experimental design. The four major factors chosen were enzyme load (10–30 wt% based on substrates), reaction time (7–18 h), reaction temperature (40–60 °C) and substrate mole ratio (terebinth oil:SA:CA 1:1:1–1:1:3). The best fitting quadratic model was determined by regression and backward elimination. Based on the fitted model, the optimal reaction conditions for the incorporation of CA and SA were found to be temperature 50 °C; time 18 h; enzyme load 30 wt%; substrate ratio 1:1:3. Under these optimum conditions, the incorporation of SA and CA could be obtained as 19 and 14%, respectively.     

A comparative study on water-based coatings prepared in the presence of oligomeric and conventional protective colloids

Poly(vinyl acetate-co-butyl acrylate) latexes were prepared by using semi-continuous emulsion polymerization method in presence of two different protective colloids which were oligomeric N-methylol acrylamide and conventional poly(vinyl alcohol). The effects of these protective colloids on colloidal, surface and film properties of latexes were examined. Poly(vinyl acetate-co-butyl acrylate) synthesized with oligomeric N-methylol acrylamide, which was characterized by FT-IR, NMR and MALDI-TOF MS, was found to have lower viscosity, finer particle size, better latex stability, lower polydispersity, higher T_g and better film forming behavior compared to those synthesized from the poly(vinyl alcohol).     

Selective CO oxidation over promoted Au/γ-Al2O3 catalysts in the presence of CO2 and H2O in the feed

In this work, the effect of promoter type (Mg, Mn, Ce, Co, Fe and Ni) on selective CO oxidation performance of Au/γ-Al₂O₃ was studied with the realistic feed stream containing CO₂ and H₂O. The effects of Au loading, promoter loading, reaction temperature and the feed composition were also investigated. It was found that MgO was the best promoter in the presence of CO₂ and H₂O, and 1.25 wt.% Mg was sufficient for promotion. The CO conversion decreased with the addition of CO₂ while the presence of H₂O had some positive effects.     

Entrapment of urease in poly(1‐vinyl imidazole)/poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) network

In this article, urease was immobilized in a conducting network via complexation of poly(1‐vinyl imidazole) (PVI) with poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPS). The preparation method for the polymer network was adjusted by using Fourier transform infrared (FTIR) spectroscopy. A scanning electron microscope (SEM) study revealed that enzyme immobilization had a strong effect on film morphology. The proton conductivity of the PVI/PAMPS network was measured via impedance spectroscopy, under humidified conditions. The basic characteristics (Michealis‐Menten constants, pH_opt, pH_stability, T_opt, T_stability, reusability, and storage stability) of the immobilized urease were determined. The obtained results showed that the PAA/PVI polymer network was suitable for enzyme immobilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

One-pot two-step lipase-catalyzed synthesis of α,ω-thiophene-capped poly(ε-caprolactone) macromonomers and their use in electropolymerization

Macromonomers based on poly(ε-caprolactone) (PCL) with α,ω-thiophene functional end groups were prepared in bulk by enzymatic polymerization using immobilized Candida Antarctica lipase B (Novozym 435) as the catalyst. In the synthesis strategy, 3-thiophenemethanol was used to initiate the enzyme-assisted ring-opening polymerization of ε-caprolactone (ε-CL) to yield PCL with α-thiophene end group (initiation reaction, ThPCL) and then 3-thiopheneacetic acid was added to prepolymerized ε-CL to introduce ω-thiophene functionality in termination step (ThPCLTh). Macromonomers were characterized by ¹H and ¹³C NMR, FTIR, and GPC. Moreover, the obtained macromonomers were employed in electropolymerization experiments and copolymers with thiophene or pyrrole were synthesized through their end thiophene groups. These polymers were characterized by cyclic voltammetry (CV), FTIR, and scanning electron microscopy (SEM). Conductivity measurements were carried out by the four-probe technique.     

Synthesis and characterization of tetrakis‐ derivatives of bisphenol‐A with 4‐phenylazoaniline and 5‐(4‐aminophenylazo)‐25,26,27‐tribenzoyloxy‐ 28‐hydroxycalix[4]arene

The synthesis of tetrakis‐ derivatives of bisphenol‐A containing azo groups at their 2,2′,6,6′‐positions is reported. Novel examples of bisphenol‐A, coupled with diazonium salts and derived from 4‐phenylazoaniline and 5‐(4‐aminophenylazo)‐25,26,27‐tribenzoyloxy‐28‐hydroxycalix [4]arene, have been synthesized. It has been observed that the coupling reaction of diazonium salt obtained from 4‐phenylazoaniline with bisphenol‐A gives tetrakis‐ while those derived from 5‐(4‐aminophenylazo)‐25,26,27‐tribenzoyloxy‐28‐hydroxycalix [4]arene give partially substituted bisphenol‐A analogues. The newly prepared tetrakis‐azo substituted bisphenol‐A compounds ( 1 and 2 ) are characterized by using UV‐vis, FT‐IR, ¹H‐NMR spectroscopic methods as well as elemental analysis techniques. These azo compounds give rise to bathochromic shifts in the absorption spectra, which can even be detected by “naked eye.” © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Adsorption of selenite and selenate ions onto thiourea‐formaldehyde resin

In the present work, thiourea‐formaldehyde (TUF) chelating resin was synthesized and used in the adsorptions of selenite (SeO) and selenate (SeO) ions. The effects of initial acidity and initial selenium concentrations on the adsorptions were examined by batch technique. The synthesized resin was applied to the elemental analysis to determine its composition. FT‐IR spectra and SEM/EDS were also recorded before and after selenite adsorption. It was found that selenite and selenate ions were adsorbed onto TUF resin at strong acidic conditions (3–5M HCl). The adsorption capacities of the resin were calculated as 833.3 mg g^?1 TUF resin for selenite ions and 526.3 mg g^?1 TUF resin for selenate. All the adsorption data obtained for both selenite and selenate ions fitted well to the Langmuir isotherm. It was seen that the adsorption mechanisms in the both adsorptions were governed by the reduction of selenite or selenate to elemental selenium, Se⁰. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

A new photopolymerization system for vinyl monomers

A mixture of Ce⁺³ salt and an aminomethylene phosphonic acid, such as amino tri(methylene phosphonic acid) (ATMP), diethylene triamine penta(methylene phosphonic acid), N,N‐di(methylene phosphonic acid) ethanol amine, N,N‐di(methylene phosphonic acid)‐N‐methylamine, N‐oxo‐N,N,N‐tri(methylene phosphonic acid), or 1‐hydroxy‐ethylidene‐1,1‐diphosphonic acid, was used for the photopolymerization of acrylonitrile, vinyl acetate, acrylic acid, and styrene in water. Molecular weights of the polymers decreased with increasing concentration of both Ce⁺³ salt and ATMP. The effect of oxygen, light, pH, and the addition order on polymerization were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2494–2499, 2002     

Effect of conductive layer on the performance of gel electrolyte-based supercapacitors

Solid-state electrolytes such a further novel finding is going to have great importance because of the disadvantages of liquid electrolytes such as electrochemical instability, low ion selectivity, and interface contact. It is anticipated that the use of solid-state electrolytes including supercapacitors (SCs) will become widespread with decreasing self-leakage and environmental damage more than liquid electrolytes. In this study, SCs with graphene/PEDOT: PSS coated electrodes and binary PVA gel electrolytes with a conductive layer were designed and the electrochemical performance of the configurations was characterized. The effects of the conductive layer between binary electrolytes and the concentration of the KOH solution in the electrolytes were studied. It was observed that the conductive layer used between the gel electrolytes causes additional charging at the electrolyte/conductive layer interface and behaves like a serially connected capacitor to the double-layer capacitor. Interestingly, at a slow sweep rate (5 mV/s), the specific capacitance values of the assembled SCs decreased when a conductive layer was used but it increased when the sweep rate was fast (100 mV/s).     

Nanoflower hydroxyapatite's effect on the properties of resin-based dental composite

To investigate the reinforcing effect of nanoflower-like hydroxyapatite (NFHA) in resin-based dental composites, we synthesized a novel NFHA using microwave irradiation (MW), hydrothermal treatment (HT), and sonochemical synthesis (SS). Silanized NFHA was then used as the reinforcing filler in dental resin composites. We characterized the structure and morphology of various HA nanostructures using x-ray diffraction, scanning electron microscope, and TEM. The mechanical performance of dental resin composites reinforced with silanized NFHA was measured using a universal testing machine. Spherical HA, synthesized through chemical precipitation (CP), served as the control group. One-way analysis of variance was employed for the statistical analysis of the acquired data. The results demonstrate that the nanoflower morphology significantly was improved mechanical and physical properties. After conducting trials, the NFHA synthesized using MW and HT showed a substantial enhancement in mechanical and physical properties compared to the other structures. Therefore, it can be concluded that NFHA can serve as a novel reinforcing HA filler, providing regenerative properties to resin composites with sufficient mechanical strength.