Journal of Applied Research in Chemistry
Year:2018 | Volume:11 | Issue:4 |Papers Count:14

Poly-caprolactone (PCL) has been widely used as scaffolding material for tissue engineering applications due to its good biocompatibility and suitable mechanical properties. However, lack of suitable surface functional groups is one of limitations related to cell attachment of this material. In this work, gelatin was coated on the surface of PCL films using physical entrapment process. Polymeric solution (acetic acid- 5%wt PCL) was cast in a glassy mold then mold remained under vacuum for 24 hours in order to evaporate acetic acid and create of film. The composition of water- acetone system (water is dissolving gelatin and acetone is swelling the surface of the film) is the critical point in performance of the physical entrapment process; so different composition was made and gelatin was dissolved in them. PCL film was immersed in each gelatin solutions for different times. In order to improve the attachment of the gelatin on the surface of PCL, chemical crosslinking was done by glutaraldehyde solution. Quality of coating layer was evaluated by using Attenuated Total Reflection–Fourier Transform Infrared spectroscopy (ATR-FTIR). Thickness of PCL film and gelatin coating was estimated by Scanning electron microscopy (SEM). Contact angle measurement (Sessile drop) was done to analysis surface wettability before and after coating process. Mechanical properties also measured by strip tensile test. Results showed that amount of entrapped gelatin increased by increase of acetone in gelatin solvent. Mechanical strength increased to two fold also young modulus and elongation improved about 50% due to surface modification. In addition Surface modification improved wettability.

Application of carbon quantum dots as nano sensors for determination of ions and molecules is an effective, fast, cheap, and environmentally friendly method and no need to complex equipment. In the present study, Mo (VI) was determined by carbon quantum dots in real samples such as tap, mineral, river waters, and tomato samples. Carbon quantum dots were synthesized by microwave assisted method. Fourier transform infrared (FT-IR) and transmission electron microscope (TEM) were used for characterization and size determination of these carbon quantum dots. At optimum conditions (pH=3, lex = 370 nm and  lem = 450 nm), detection limit and linear dynamic range were 24 nM and 0.2- 50 mM, respectively. Fluorescent quenching process was very fast that was an important advantage of this nanosensor. Interference effects of other ions on Mo (VI) determination (at constant concentration of 25±0.072 mM, n=3) by carbon quantum dots were investigated in the presence of different concentration of other species.

Here, we demonstrate the synthesis of Pt nanoparticles integrated on graphene/cobalt oxide (CoO) architecture (Pt/CoO-GNS) through a facile hydrothermal method. The synthesized catalyst was characterized by X-ray diffraction and the morphology of it was studied by scanning electron microscopy. The obtained results indicated that the sample had unique tolerable porous structure. This structure can supply sufficient mass transfer channels and plenty of active sites on Pt/CoO-GNS to assist the catalytic reaction. The synthesized Pt/CoO-GNS was prospected as an electrocatalyst for the oxygen reduction reaction and presented comparable oxygen reduction performance with outstanding methanol resistance. In addition, the astability of this catalyst was improved in comparison with Pt/C.

In this study, nano-macro magnesium oxide was synthesized with different structures, such as cube and spherical, by using different ratio arginine and urea as additives without making use of any surfactants by a hydrothermal method at 130-180oC during 24 hours. Nanoparticles were calcinated at 400oC to obtain particles of sizes between 42 to 80 nm. The samples characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), adsorption and desorption of nitrogen test (BET), infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-Vis), and ׳ EDX. Nifedipine, as an insoluble drug, was loaded on magnesium oxide substrate (sample MgO1 and MgO2). The in vitro drug release was investigated in simulated intestinal fluid (pH = 6.8) and simulated gastric fluid (pH = 1.2). At the simulated intestinal fluid (pH = 6.8), the amount of drug release enhanced to 100% for sample MgO2 (cubic structure) after15 hours. The Korsmeyer– and MgO2. ׳ Peppas models were applied to evaluate the kinetics of nifedipine release from MgO1 The results showed that the kinetic of the drug release was non-ficken in both SGF and SIF.

Waste EPDM was recycled by using a twin-screw extruder in the thermo-mechanical method; and the effects of processing parameters were investigated. Barrel temperature (220, 280, 340 and 380oC) and screw speed (60, 100 and 140 rpm) were chosen as the variables. Devulcanized characterizations, such as devulcanization percent, solvent swelling, and sole fraction were studied. After curing, the properties of revulcanized compounds (including 30 phr devulcanized EPDM) were compared with the reference compound (100% new EPDM compound). At low temperature and low screw speed, devulcanization was poor while with increasing both of them, devulcanization occurred very significantly indicated as higher solvent swelling. On the other hand, sole fraction increased as a function of processing conditions. Mooney viscosity decreased for high processing parameters; higher sole fraction, lower Mooney viscosity. Normally, compounds having 30 phr devulcanized rubber showed properties poorer than the reference one, but closer to evaluating devulcanization conditions. As the temperature or speed increased, stronger tensile behavior, reduced pressure set, and less creep elongation were achieved, meaning more crosslinks breakdown and successful revulcanization.

Green chemistry using the extract of plants is one of the cheapest natural methods for synthesizing nanoparticles, which can be taken into consideration along with other physical and chemical methods. In this study, the leaf extracts of Thymus trautvertteri as the reducing agent, was used for the biosynthesis of silver nanoparticles. By adding silver nitrate in a concentration of 1 mM to extract, the reaction carried out at room temperature which color change from pale yellow to dark brown was the first visible sign of the synthesis of silver nanoparticles. Biosynthesized silver nanoparticles were characterized using UV-Visible absorption spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (FESEM). The UV-Visible spectrum showed a peak at 470 nm corresponding to the plasmon absorption of the AgNPs. X-ray diffraction pattern confirmed the formation of crystalline structure of silver nanoparticles. FT-IR results also indicated the role of different functional groups in the synthesis process. Transmission electron microscopy (TEM) and scanning electron microscopy (FESEM) analyses shows the synthesized AgNPs are predominantly spherical in shape with average particle size less than 50 nm. Also, the antibacterial properties of nanoparticles against Staphylococcus aureus and Escherichia coli were evaluated by disk diffusion method in Agar, which had a good inhibitory effect on the activity of these bacteria. The proposed synthesis method is eco-friendly and can be potentially used for large-scale production of AgNPs.

Liquid fuel dimethyl amino ethyl azide (DMAZ) is a novel and carcinogenic fuel in space industries. To satisfy the space standards in the fuel production, the water from the process should be removed by adsorption. In this research, 4A nano-zeolite was synthesized using hydrothermal method for dehydration of liquid fuel dimethylaminoethylazide (DMAZ). In order to calculate the adsorption capacity, the experimental data were collected and fitted with various isotherms. The obtained results showed that the Langmuir isotherm describes well the adsorption behavior of 4A zeolite. Also, to investigate the penetrating of DMAZ molecules into pores of zeolite, firstly, the penetration was evaluated by Koresh-Soffer theory, and then, validated using the thermal analysis. The results reveal that the DMAZ molecules cannot penetrate into zeolite pores and the zeolite is perfectly suited for dehydration. This leads to no losses of the fuel during purification process in industrial scale.

In biological fluids, chitosan hydrogel has become a potential candidate for carriers of bioactive molecules and controlled release of drugs in their swollen state. The prepared film of cross-linked chitosan utilized as a medium for delivery of podophyllotoxin in skin diseases. The drug delivery systems can reduce side effects of toxins and provide a high concentration of drug at the site. Physicochemical properties of prepared film, such as swelling behavior and release rate were studied. Some parameters have influenced on hydrogel swelling including cross linker concentration, temperature, and pH. The prepared hydrogel shows maximum swelling at the lowest PH. Hydrogel films with 15% glutaraldehyde as a cross linker have good behavior for drug release. Formulations prepared from chitosan and acryl amide have good behavior, but the concentration of cross linker has a negative effect. Drug release profile in this film follows the first rate model.

In this work, nanomagnetic hydrogels based on arabic gum (AG) were used for removal of crystal violet in aqueous solution. The hydrogels were first prepared by free radical polymerization of acryl amide (AAm) and 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) in the presence of arabic gum using N,N′-methylenebis (acrylamide) (MBA) as a crosslinker agent and ammonium persulfate (APS) as an initiator. Then, nanocomposite hydrogels were prepared via in situ reduction of loaded Co2+ ions by using sodium borohydride. The effect of different variables, such as contact time, initial concentration of dye, temperature, and pH of solution, were investigated on the sorption behavior of the crystal violet. The structure of the hydrogels was characterized by FT-IR spectroscopy, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The results of scanning electron microscopy show that the magnetic nanocomposite has a good dispersion in the hydrogel matrix and the approximate size of the particles are about 10-30 nm. The results of this study show that the nanomagnetic hydrogels with high removal efficiency and low reaction time can be used as effective adsorbents for the removal of crystal violet dyes from aqueous solution. The adsorption isotherm show that the adsorption of crystal violet on the nanocomposite hydrogels follow the Temkin adsorption model.

In this paper, the synthesis of novel 1-benzyl-3-((2, 3-dioxoindolin-1-yl) methyl) pyridinium bromide is reported. The products were synthesized in two steps from isatin and 3-(chloromethyl) pyridine or 4-(chloromethyl) pyridine derivatives in basic conditions. The inhibition activity of the products was studied against acetyl- and butyryl-cholinesterase. The results showed that, 4-pyridine derivatives had higher activities than 3-pyridine derivatives. In addition, among 4-pyridine derivatives, the best activities were related to 5a, 5b, 5c, 5g, and 5h, while 5b had the highest inhibition activity by IC50 = 1.00 mM, which could be applied in the treatment of Alzheimer desease.

Levodopa is a precursor of the neurotransmitter dopamine used in the treatment of Parkinson’s disease. Determination of this drug in biological samples is very important for monitoring of its therapeutic effect. In this study, corona discharge ion mobility spectrometry (IMS) was applied as a rapid and efficient method for determination of this drug in different samples. Injection and oven temperatures, gas flow rate and corona voltage were optimized as experimental parameters influencing both detection and determination efficiencies. By this method, levodopa was determined with low detection limit (1.17 ng. ml-1) in very short time and good recoveries (96.3-98.6%) without needing any complicated preparation and organic solvents. For selective and sensitive determination of levodopa in urine sample, levodopa was extracted using a magnetic Iron graphene nanocomposite as a solid phase. The proposed method shows a solid phase extraction procedure followed by IMS can be successfully applied for the simple, inexpensive, rapid, and sensitive determination of drug compounds in biological samples.

In this study, chlorosulfonyl calix[4]arene bound to silica (CSC[4]A-SiO2) was synthetized to study the adsorption behavior of some chemical additives used in rubber industry, such as diphenylguanidine (DPG), N-Cyclohexyl-2-benzothiazolesulfenamide (CBS), and 2-mercaptobenzothiazole (MBT). According to our results, CSC[4]A-SiO2 by interacting with DPG and CBS (which are used as ordinary accelerators in the manufacture of rubber compounds) can be applied as a selective sorbent in this regard. The greatest amount of adsorbed DPG and CBS by this adsorbent was estimated to be 49% and 55%, respectively. The electrostatic interaction and hydrogen bonding between hydroxyl groups of calix[4]arene moiety and the NH group of DPG and CBS molecules are the probable interactions responsible for the removal of these compounds.