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Chitosan/feldspar biobased beads were synthesized, characterized, and tested for the removal of Acid Black 1 dye from aquatic phases. A four-factor central composite design (CCD) accompanied by response surface modeling (RSM) and optimization was used to optimize the dye adsorption by the adsorbent (chitosan/feldspar composite) in 31 different batch experiments. Independent variables of temperature, pH, initial dye concentration, and adsorbent dose were used to change to coded values. To anticipate the responses, a quadratic model was applied. Analysis of variance (ANOVA) tested the significance of the process factors and their interactions. The adequacy of the model was investigated by the correlation between experimental and predicted data of the adsorption and the calculation of prediction errors. The results showed that the predicted maximum adsorption amount of 21.63 mg/g under the optimum conditions (pH 3, temperature 15°C, initial dye concentration 125 mg/L, and dose 0.2 g/50 mL) was close to the experimental value of 19.85 mg/g. In addition, the results of adsorption behaviors of the dye illustrated that the adsorption process followed the Langmuir isotherm model and the pseudo-second-order kinetic model. Langmuir sorption capacity was found to be 17.86 mg/g. Besides, thermodynamic parameters were evaluated and revealed that the adsorption process was exothermic and favourable.

In this article, the graphene oxide (GO) was produced from graphite by the “modified hammer” method. Then in order to achieve electromagnetic absorption, GO was reduced and modified two times. First, it was reduced and modified by Cr, and then for the second time, it reduced and remodified in a one-step process with FeCl2 and FeCl3. All the synthesized materials were characterized via SEM, TEM, XRD, FTIR, Raman spectroscopy. These methods showed that in each stage Cr-RGO and Fe–Cr-RGO were successfully produced and the method that has been used was prosperous. To investigate prominent electromagnetic (EM) absorption, every specimen was added to the epoxy matrix with different concentrations and molded with different thicknesses. To perfectly disperse modified reduced graphene oxides powder in the epoxy resin, a unique liquid Ions (Butyl methyl imidazolium bromide) was used. This product has a key role in dispersing the material into the matrix and in the meantime the resulted composites showed a better return loss (RL) in the network analyzer tests. With a series of tests and precise measurements, the optimum thickness and concentration of Cr-RGO or Fe–Cr-RGO to reach the maximum EM absorption were developed. The result shows that by increasing the concentration and the thickness of the specimens, electromagnetic absorption increases and this phenomenon has happened almost in the complete range of our desire microwave (MW) wavelengths (2–12 GHz).

Ofloxacin (OFL) is an antibiotic with a wide range of bacterial infections but its low water solubility and photo stability restricts its applications, so improve its solubility and stability is a challenge. Inclusion complex formation between α-cyclodextrin (α-CD) and OFL was prepared under various circumstances to obtained desirable water solubility. The effect of polyethylene glycol physiologically compatible solubilizing agent and mixing condition were investigated in the formation of an inclusion complex between α-CD/OFL. FTIR, H-NMR, DSC and XRD results indicated the formation of an inclusion complex between α-CD/OFL. Phase solubility test for obtaining α-CD/OFL complexes indicated a rise in aqueous solubility of OFL and formation of inclusion complexes and obviating OFL aqueous solubility limitation. SEM and EDX results indicated OFL/CD/PVA nanofibers without beading defect. Antibacterial activities of OFL/CD nanoparticles were investigated by them inhabitation of bacteria growth. Obtained nanofibers showed significant antibacterial effect against Escherichia Coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

The use of ultrasonic for accelerating the chemical and physical processes of wool has gained high importance. This study aims to develop a method for reducing the energy and material consumption and decreasing fiber damage. Ultrasonic equipment (20 kHz) was used for grafting chitosan to wool fabric. Experiments were carried out under different times and chitosan concentration. The results showed using this technique decreases the time required for grafting chitosan onto wool which is less than the other procedures. Differential scanning calorimetry, Fourier transform infra-red, and weight gain analyses provided evidence that chitosan was grafted onto the acylated wool through the formation of new covalent bonds in a short time. Scanning electron microscope was used to study the morphology of wool samples before and after modification. The dyeing of the chitosan grafted-acylated wool fabrics indicates higher dye ability and lower shrinkage compared to the acylated and raw wool samples. The findings of this study support the potential of using ultrasonic as a friendly environment method for grafting chitosan onto wool with enhanced dye ability and reduced shrinkage properties. The grafted samples showed good antibacterial properties against Staphylococcus aureus as gram-positive and Pseudomonas aeruginosa as gram negative bacteria. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Poly caprolactone and chitosan were used to fabricate multi-layer scaffolds using electrospinning technique. The effect of layers arrangement on the biological and mechanical properties of the nanofibrous multilayer composites was studied. PCL was dissolved a) in methylene chloride/dimethyl formamide (MC/DMF 4:1) to make 10% solution and, b) in 90% aqueous acetic acid (90AA) to make 15% solution. Chitosan/PVA (2:3) was dissolved in 80% aqueous acetic acid. Nanofibers webs were prepared from each solution under constant conditions. The number of layers were varied from 2-4 to make the final samples. SEM was used to study the morphology of the webs. Cross sectional micrographs show the interface of layers and the layer arrangements. Mechanical properties of the webs were measured by Universal testing machine. The results show that the webs containing PCL dissolved in 90AA had better mechanical properties. The porosity of each nanofibrous layer was calculated and the results showed that the porosity of PCL in MC/DMF is better than the others. MTT assay was carried out on the resulted nanofibrous web to investigate the proliferation rate of fibroblast cells on the scaffolds. SEM micrographs also were used to study the morphology of cells adhering on the nanofibrous scaffolds. [ABSTRACT FROM AUTHOR]

Polycaprolactone nanofibers were prepared using five different solvents (glacial acetic acid, 90% acetic acid, methylene chloride/DMF 4/1, glacial formic acid, and formic acid/acetone 4/1) by electrospinning process. The effect of solution concentrations (5%, 10%, 15% and 20%) and applied voltages during spinning (10KV to 20KV) on the nanofibers formation, morphology, and structure were investigated. SEM micrographs showed successful production of PCL nanofibers with different solvents. With increasing the polymer concentration, the average diameter of nanofibers increases. In glacial acetic acid solvent, above 15% concentration bimodal web without beads was obtained. In MC/DMF beads was observed only at 5% solution concentration. However, in glacial formic acid a uniform web without beads were obtained above 10% and the nanofibers were brittle. In formic acid/acetone solution the PCL web formed showed lots of beads along with fine fibers. Increasing applied voltage resulted in fibers with larger diameter. [ABSTRACT FROM AUTHOR]

The article presents a study which synthesized a water-soluble chitosan derivative, N-(2-hydroxy) propyl-3-trimethylammonium chitosan chloride (HTCC) by the reaction of chitosan with glycidyltrimethyl ammonium chloride. Results showed that polymers are immiscible even at low percentage of HTCC. It was also found that blending polyacrylonitrile (PAN) with HTCC enhances the dyeing behavior of the blend films and fibers.