Synthesizing tertiary silver/silica/kaolinite nanocomposite using photo-reduction method: Characterization of morphology and electromagnetic properties

Silver was loaded on silica/kaolinite by photo-reduction technique. The present study investigated the effects of the UV irradiation on different characteristics of the particles employing X-ray diffraction (XRD), Fourier-transform infrared spectra (FTIR), UV–vis spectrophotometer (UVS), Brunauer–Emmett–Teller specific surface area method (BETM), zeta potential measurement (ZPM), thermal gravimetric analysis (TGA), scanning electron microscope (SEM), electron dispersive X-ray spectrometer (EDX) and electromagnetic transition instrument (ETI). XRD, FTIR as well as UV absorption methods evidenced that synthesizing procedure was successful under UV irradiation. TGA results demonstrated that the Ag nanoparticles (AgNPs) generated on the silica/kaolinite surface can decrease thermal stability of particles due to proton delocalization of hydroxyl groups and Hofmann–Klemen effect. EDX results showed the presence of chemical elements namely Fe, Al, Si, Mg, K, Ti, Ag, Ca and Fe on the surface of tertiary nanocomposite. The synthesized silver/silica/kaolinite particles were found to have a higher electromagnetic absorption activity compared with silica/kaolinite. As a result, they can be used in polymer-based composites for preparing high performance electromagnetic interference shielding materials.     

A new approach to improve dyeability of nylon 6 fibre using a subtilisin enzyme

This study confirms the structural changes of nylon 6 fibres using protease by measuring the dyeability, hydrophilicity, chemical changes and fastness properties. For this purpose, nylon 6 fabrics were first treated with different concentrations of protease enzyme in aqueous solutions. The dyeing process was then carried out on the treated fabrics with disperse and acid dyes. Acid and disperse dyes showed higher exhaustion on the enzyme‐treated samples. The results of colour measurement in the CIELAB system showed that the darkness of the samples increased with an increase in the enzyme percentage in the solution. The results of moisture regain showed that treatment of nylon fabrics with a proteolytic enzyme caused an increase in moisture absorbency. The wash and light fastness properties of samples were measured according to ISO 105‐C05 and daylight ISO 105‐B01 and are discussed.     

A Study on Passive and Electrochemical Response of Pure Nickel in Borate Buffer Solutions: Effect of Cold Deformation

In the present work, influences of the cold deformation on electrochemical and passive response of pure nickel in three solutions with adjusted pH values of 8.5, 9.0, and 9.5 at 298?±?1 K (25?±?1 °C) were investigated. A cold deformation process was applied by means of cold rolling. Implementation of the cold deformation process resulted in samples having a finer microstructure. Also, the cold work and grain refinement led to increased hardness. In addition, open-circuit potential and potentiodynamic polarization tests were performed and results showed that corrosion current density was reduced by applying the cold deformation. Moreover, the results of the electrochemical impedance spectroscopy and Mott–Schottky analyses indicated higher corrosion resistance of pure nickel after cold deformation. This behavior is attributed to the growth of much thicker, with less point defects, passive layer on the surface of cold-deformed samples.     

Preparation of water-repellent cellulose fibers using a polycarboxylic acid/hydrophobic silica nanocomposite coating

This research was carried out to embed hydrophobic silica nano-particles on the cotton surface using 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent and sodium hypophosphite as a catalyst. The influence of the amount of silica nano-particles on the performance of the cotton fibers was investigated employing Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy (RS), Thermogravimetric analysis (TGA), limited oxygen index (LOI), scanning electron microscopy (SEM), water contact angle (WCA), reflectance spectroscopy (RS) and abrasion resistance (AR). The possible interactions between silica nano-particles, the crosslinking agent and the cotton functional groups at the surface were elucidated by ATR-FTIR and Raman spectroscopy. The results indicated that the embedded silica nano-particles modify the surface of fibers increasing the hydrophobicity and thermal stability of substrate. The microscopic analysis showed a uniform coating of silica nano-particles on the surface of fibers.     

The Effects of Softeners on the Properties of Sulfur-Dyed Cotton Fibers

The processing of textiles to achieve a particular handle is one of the most important aspects of finishing technology. Softeners can improve some properties of textiles, depending on the chemical nature, including soft handle, smoothness, elasticity, hydrophilic, antistatic and soil release properties. They can affect the color and fastness of the dyed textile. In this research project, cotton fabrics were first scoured with nonionic detergent and then dyed with four sulfur dyes of different structures. The colors of the dyed fabrics was yellow, bluish black and bright blue. The dyed fabrics were then treated with anionic, cationic, nonionic, micro and macro silicone softeners. Nonionic, micro and macro silicone softeners decreased the lightness (L*) of all sulfur-dyed samples while anionic and cationic softeners caused only a slight alteration in lightness. The a*, b* and c* values of most dyed samples showed a little change after treatment with softeners except for the color coordinates of the yellow samples, which increased. A considerable increase in the fk values for silicone softener-treated samples was obtained. The washing fastness properties of blue samples decreased while they remained unchanged for other samples. The light fastness properties decreased for all samples after treatment with softeners.

Electrochemical Behavior of Passive Films Formed on the Surface of Coarse-,Fine-and Ultra-fine-Grained AA1050 Based on a Modified PDM

Electrochemical impedance spectroscopy(EIS) and Mott-Schottky analysis were carried out to evaluate the electrochemical behavior of the passive films formed on the surface of coarse-grained(CG),fine-grained(FG) and ultrafine-grained(UFG) 1050 Al alloy(AA1050) samples in alkaline media(pH value of 8.0) based on a modification of point defect model(PDM).The EIS results revealed that the polarization resistance increased from about 22.71-120.33 kΩ cm~2for UFG sample when compared to CG sample(annealed sample).The semiconductor properties of the passive films formed on CG,FG and UFG AA1050 samples in the test solution were investigated by employing Mott-Schottky analysis in conjunction with PDM.The results indicated that donor densities were in the range of 2.19 × 10~(21)-0.61 × 10~(21) cm~(-3)and decreased with grain refinement.Finally,all electrochemical tests showed that the electrochemical behavior of AA1050 alloy was improved by decreasing the grain size,mainly due to the formation of thicker and less defective oxide films.     

Extraction of juglone from Pterocarya fraxinifolia leaves for dyeing,anti‐fungal finishing,and solar UV protection of wool

In many countries, the search for new sources of natural colourants has recently been intense. This paper deals with the extraction procedure, dyeing behaviour, antifungal activity, and ultraviolet protection of Pterocarya fraxinifolia as a new natural source of dyes. Juglone was found as the main extracted compound after characterisation by ultraviolet‐visible spectrophotometry and Fourier transform infrared spectroscopy. Mordanting and subsequent dyeing of wool with extracted juglone were then performed to study the dyeability and antifungal activities. Three metal salts, aluminium sulfate, copper sulfate, and iron sulfate, were used as chelating materials. The colorimetric properties of samples were evaluated using a reflectance spectrophotometer. Furthermore, the washing and light fastness properties were tested according to ISO 105‐CO3:1989 and ISO 105‐B01:2014. Interestingly, we found P. fraxinifolia to be a source of strong antifungal compounds against microorganisms. Extracted juglone also exhibited strong protection activity against solar ultraviolet rays.     

Effect of nanoclay type on dyeability of polyethylene terephthalate/clay nanocomposites

Polyethylene terephthalate (PET)-based nanocomposites containing three differently modified clays were prepared by melt compounding. The influence of type of clay on disperseability, thermal, and dyeing properties of the resultant nanocomposite was investigated by various analytic techniques, namely, X-ray diffraction, optical microscopy (OPM), differential scanning calorimetry, thermal gravimetric analysis, dynamical mechanical thermal analysis, contact angle measurement (CAM), reflectance spectroscopy, and light fastness. OPM images illustrated formation of large-sized spherulites in pure PET, while only small-sized crystals appeared in PET/clay nanocomposites. Decreased glass transition temperatures for all PET/clay nanocomposites indicate that the amorphous regions of such composites become mobile at lower temperatures than those in pure PET. CAMs on the resultant PET composites demonstrated that the wettability of such composites depends on hydrophilicity of the nanoclay particles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Coating of macroemulsion and microemulsion silicones on poly(ethylene terephthalate) fibers: Evaluation of the thermal properties and flammability

Silicone softeners are widely used in the textile industry to improve the soft handling and aesthetic feel of textiles. These compounds can influence the thermal characteristics and flammability of polyester fabrics, which need to be addressed as important issues of human safety. To do this, the thermal degradation and flammability of macroemulsion and microemulsion silicone coated polyester fibers were studied with various analytical techniques, namely, differential scanning calorimetry, thermogravimetric analysis, dynamical mechanical thermal analysis, and limited oxygen index testing. It has been stated that the electrostatic and hydrophobic interactions of silicone emulsions with polyester can affect their thermal stability. On the other hand, the silicone emulsions present on the surface of poly(ethylene terephthalate) provide a three-dimensional scaffold, which produces faster combustion than pyrolysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal Characterization and Flammability of Polyester Fiber Coated with Nonionic and Cationic Softeners

The aim of this research was to study the effect of nonionic and cationic softeners on the thermal degradation of polyethylene terephthalate fibers. The influence of the type of emulsion on the thermal properties and flammability of the resultant samples was investigated by various analytical techniques, namely, differential scanning calorimetry, thermal gravimetric analysis, dynamical mechanical thermal analysis, and the horizontal flammability test. Results showed that softeners with different ionic structure have different effects on thermal degradation and flammability of polyethylene terephthalate substrates.