نشریه علوم و فناوری رنگ
سال سیزدهم شماره 1 (پیاپی 47، بهار 1398)

In this research, manganese hydrogen sulfate as a novel green catalyst was used to synthetize diazo dyes. Manganese hydrogen sulfate was used as a hydrogen source to produce diazonium salt and then, the obtained anion formed a stable gel with diazonium salt at room temperature which was stable until 70 °C.  Moreover, in order to produce diazonium salts, synthetic heterocyclic amines were utilized. The proposed heterogeneous acidic catalyst, manganese hydrogen sulfate, can be applied in industrial scale due to the advantages such as environmentally friendly features and easy catalyst transfer. This method provides several advantages such as, high-efficiency catalyst, mild operational conditions, room temperature conditions, low cost, availability, easy catalyst preparation, and a simple workup procedure.

Contact angle measurement of a drop on surface is known as a common method for determining the surfaces wettability. Although the drop contact angle measurement on horizontal surface is fully-described, but contact angle measurement for the asymmetric drop on inclined and specially curved surfaces, mainly is analyzed by tangent line method, suffers from inadequate accuracy and speed. The main objective of this study is to introduce an effective algorithm for determining the contact angle of drops on inclined and curved surfaces without using fluid parameters such as density and drop volume. For this purpose, real and artificial image of drops are used. The developed method uses side view image of drops and creates the binary matrix of the image by using the Otsu method. Then, the solid-fluid-fluid interface is detected and the contact angle is calculated by means of determining the derivative at the three phases contact point. One problem which contact angle measurement faces with is determination of the location of  three-phase contact point, instead of calculating the derivative based on just one pixel, averaging of several pixels are used to reduce effect of this problem. In order to validate the proposed method, real images of the drops of four different fluids on the calcite surface, as well as artificial images created with the aid of graphic software with a specific contact angle, are used. The results show the accuracy of the proposed method for contact angle measurement of the symmetric and asymmetric drop on horizontal, inclined and curved surfaces.

In this study the natural colorants of Jasir, Madder and Pomegranate skin are considered to be compatible with wool yarns. To this end, the ability to dye each of the dyes of aluminum doped and dentinite sulfates was used as one of the most commonly used methods. The calculation results of this method showed that the dyeing curve of the three colors of dessert and reno are similar to each other. While the ability to dye wool yarn varies with dye of the skin of the pomegranate, it differs from that of the other two dyes. In this way, the similarity of the dyeing ability of the two gestures and the rhine reflects the relative adaptability of these colored materials. While the difference between the dyeing curve of pomegranate skin is low compatibility with jersey and rhinos. After calculating the ability to dye, dyeing of woolen yarn was done by combining two colors in three different dimensions. Then the degree of color matching was measured through common computational relationships. The computational results show that the colors of Madder and Jashir are in good harmony with each other. While the combination of pomegranate peel with any of the two dyes of Madder and Jashir results in low compatibility with weak to weak grades. In addition, the results of this study showed that the two concentrations of dye in the mixed bath and the use of the tooth affect the degree of compatibility and change the degree of color compatibility. Overall, the results of this study showed that the dye of Madder and Jashir are very consistent with each other and can be considered in the bathroom for the coloring of wool. While it is not possible to combine two colorful materials with pomegranate peel due to poor compatibility grade.

In this study, piezoelectric properties of high solid piezoelectric paints (upper than 85 wt% pigment) have been investigated. High polarity particles were obtained by recyclying cores of sonar devices through cruching, milling, seizing anod surface modifying by silane groups. Structural studies revealed the presence of lead zirconate titanate (PZT) in the X-ray diffraction pattern (XRD) of paint. Microstructue confirmed the existence of PZT particles in the polymeric matrix of resin which were agglomerated to optimize piezoelectric values. Due to the loss of piezoelectric properties in submicron sizes, average of particle size was selected between 38 μm (400 mesh) and 106 μm (140 mesh). The optimized thickness was also set between 500-1500 μm for the same reason. Moreover, other studies showed that surface treatments and use of solvent in formulation had undeniable effects on piezoelectric properties of paints. The optimized Piezoelectric Coefficient d33 (22 pC/N) was achieved in the sample treated by alkaline solution. This sample also showed higher corrosion resistivity in 200 hours period of time.

Nowadays, self-healing process and compensating of the applied damages without any tracking of physical intervention has become one of the subjects of interest for researchers. Self-healing ability is especially used for protective coatings in order to enhance both stability and durability. In this study, carbon nanospheres were used to fabricate the self-healing protective coatings based on epoxy resin. In the first step, carbon spherical nanostructures were synthesized according to the hard templating method. In the second step, doping of epoxy and polyamine agents in the spherical structures were performed using vacuum jar method. Then, 8 wt. % of the epoxy doped carbon nanospheres and 4 wt. % of the polyamine doped carbon nanospheres in stoichiometry ratio were dispersed uniformly in epoxy matrix. Finally, the morphology of the synthesized carbon nanocapsules and self-healing performance of the fabricated coatings were evaluated using field emission scanning electron microscopy (FE-SEM) and scanning vibrating electrode technique (SVET). The results showed that due to the applying of artificial scratches on the coatings and fracture of the doped capsules, release of epoxy and polyamine from carbon capsules and performing of curing reactions between them led to the healing of the scratch regions.

Four 2-aminobenzothiazole derivatives (1-4) were synthesized via one pot reaction of appropriate aniline with sodium thiocyanate and bromine at room temperature. These heterocyclic amines and 2-aminobenzothiazole were diazotized by nitorsyl sulphuric acid in acetic acid and coupled with 6-amino-1, 3-dimethyl pyrimidine-2, 4(1H, 3H)-dione to afford azo dyes (5-9) in satisfactory yields. The structures of the compounds were confirmed by spectral methods FT-IR, 1H NMR, 13C NMR and UV-vis.  The effects of six organic solvents (acetic acid, ethanol, chloroform, acetonitrile, dimethyl formamide and dimethyl sulfoxide), acid, base, pH changes and substituents of the diazotizing components on the maximum absorption wavelength of the colorants were discussed and evaluated. In addition, the antibacterial activity of the synthesized dyes has been evaluated against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli bacterial strains.

Acid red 14 is an azo dye which is used widely in textile industry and due to its high consumption, is a serious environmental hazard so that in recent years, a lot of research has been done on the photocatalytic removal of azo dyes from water with nanocomposites. In this research, TiO2/Fe3O4/CNT nanocomposite was synthesized with the sonochemical method and the photocatalytic removal of acid red 14 dye was investigated in a batch reactor by OFAT method. The morphology and structure of the nanocomposite were characterized by FESEM and EDS analysis. The optimum efficiency of 96.53 for AR14 was achieved under following conditions: dye concentration of 50 mg/L, nanocomposite concentration of 0.5 gr/L, Dissolved oxygen concentration of 7.4 mg/L, pH= 7, 120 W/m2 irradiation intensity and the reaction time 6 hours. Also, the removal of photocatalytic dyes by TiO2/Fe3O4 nanocomposite showed TiO2/Fe3O4/CNT nanocomposites had better performance in dye removal than TiO2/Fe3O4 nanocomposite. It was also found that the dye removal mechanism with a regression coefficient of 0.9597 had the most overlap with the pseudo first-order reaction.