JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2020 | Volume:13 | Issue:4 |Papers Count:8

Self-curable waterborne polyurethane (WPU) dispersions were prepared via acetone process. The effects of (3-aminopropyl) triethoxysilane (APTES) content as crosslinking agent on the properties of WPUs were investigated. To confirm the polymer structure and the presence of alkoxysilane groups, 1H nuclear magnetic resonance and fourier transform infrared spectroscopy were used. Gel content of the sample containing 10 wt% APTES was reported 90. 5% which were revealed highly crosslinking network of the WPU film. Although the particle size went up from 36. 5 to 63 nm by introducing 10 wt% APTES, narrow particle size distributions (PDI < 0. 2) and the absolute value of zeta potentials greater than 40 mV were obtained. Furtheremore, atomic force microscopy showed that the introduction of siloxane crosslinking increased microphase-separation of the polyurethane films. In the presence of 10 wt% APTES, excellent enhancement in water resistance (water absorption < 5%), mechanical properties (Young’ s modulus=420 MPa and tensile strength=46. 7 MPa), and thermal stability (Tmax1=321 º C and Tmax2=407 º C) made this type of crosslinking highly suitable for WPUs in coating applications. J. Color Sci. Tech. 13(2020), 267-276© . Institute for Color Science and Technology.

Iron-gall ink is one of the varieties of inks used in the past that consists of four main components of gall nut, vitriol, gum arabic and water and due to chemical instability changes color over time. The present study tried to investigate the impact of the extract of absinthium, as well as the ratio of gall to the alum used in the manufacture of ink on stabilization of the color of irongall ink based on old references and through laboratory studies. In this study, after making two types of black ink using old sources, the samples were exposed to light and temperature-humidity aging and after examination by using acidity and colorimetric tests, it was determined that adding extracts of Artemisia absinthium to iron-gall ink can stabilize its color, and the ratio of gall to alum is also an important factor in this sustainability. J. Color Sci. Tech. 13(2020), 277-291© . Institute for Color Science and Technology.

The aim of this research was study and comparison of FT-IR and TLC results for characterization of kermes dyes in archaeological and historical fibers and assessment of their advantages and disadvantages. Samples were prepared from silk and wool fibers. The samples were artificially aged according to Feller (1994). After aging, color change and pH were measured. Fourie Transform Infrared Spectroscopy-Attenuated Total Reflectance (ATR-FTIR) was applied for assessment and comparison of aged and unaged samples. Moreover, Thin Layer Chromatography was used before and after aging by choosing appropriate solvent. Results showed after aging, pH content of dyed silk with kermes was increased and Rf in TLC indicated minor change. The ATR-FTIR spectometer results showed that there are no differences between raw and dyed fibers, therefore, the color should be extracted in order to specify the sepctrum of color ingredients. After extarcting the samples, they do not differ much with the aged ones. J. Color Sci. Tech. 13(2020), 293-303© . Institute for Color Science and Technology.

During this research, the formulation of manganese phosphate bath was designed to create layers on the surface of low carbon steel alloys (St 37) to enhance corrosion, abrasion and friction resistance. At the first. a basic solution of the manganese phosphate bath was prepared by optimizing the concentration of each components of the bath. Then, the effects of potassium oxalate and nickel oxide additives on coating properties such as thickness, unit weight of surface With optimal value of 1± 0. 1 gr/l nickel oxide, the weight of the coating 39. 8 ± 0. 2 gr/m was obtained and optimal value of 0. 5± 0. 1 gr/l potassium oxalate, the weight of the coating 48. 99± 0. 3 gr/m2 was obtained), morphology. corrosion and abrasion resistance were investigated and finally, the best coating determined. The results of various experiments showed that the major phase of manganese phosphate coating is Hureaulite, which is in the form of cubic crystals in the basic solution that does not contain any additives. of course, with the addition of additives, the shape of the crystals is changed and the particle size becomes smaller and denser. The highest corrosion resistance obtained during the salt spray test (98 hours) and electrochemical impedance spectroscopy (EIS) (with Polarization 77983± 253 ) is related to phosphate coating containing nickel oxide. According to the results of the Pin on disk test the specimens which were phosphated and soaped reduced the coefficient of surface friction from about 0. 6 (for uncoated steel) to about 0. 15. and this indicated the anti-abrasion and friction properties of these coatings. J. Color Sci. Tech. 13(2020), 305-315© . Institute for Color Science and Technology.

Synthesis of TiO2-based composite by using carbonous materials can solve some restrictions related to the application of titanium dioxide in industrial scale. In this study carbon nanotubes (CNTs), graphene oxide (GO) and reduced graphene oxide (RGO) are used to improve the photocatalytic activity of TiO2 for the degradation of methylene blue under visible light irradiation and the effect of simultaneous usage of graphene sheets and CNTs are evaluated through the enhancement of TiO2 degradation activity. The photocatalytic activity and characterization of as-prepared samples were evaluated by Fourier transform-infrared spectroscopy, Xray diffraction, Field emission scanning electron microscopy and UV-Vis Spectrophotometer. Results indicate the successful preparation of TiO2-CNT-GO nanocomposite by sol-gel method. Moreover the simultaneous using of graphene sheets and CNT can prove the composite decoloration activity. The maximum photocatalytic degradation of MB (94%) is achieved within 90 min. The enhanced photocatalytic activity of TiO2-CNT-GO nanocomposite can be ascribed to the high surface area, severe electron transmission and monotone distribution of carbon based nanoparticles. J. Color Sci. Tech. 13(2020), 317-330© . Institute for Color Science and Technology.

In this research, safflower extract was used as a green inhibitor in 0. 1 M HCl solution to evaluate the rate of corrosion of mild steel in this environment. At the first step, the extract of fresh safflower plant (SPE) was prepared. The chemical structure of SPE was recognized by Fourier Transform Infrared Spectroscopy (FTIR). At the second step the solution of 0. 1 M HCl containing 500 ppm SPE was prepared and in the next step the corrosion inhibition performances of the extract solution were proved by means of electrochemical impedance spectroscopy (EIS) technique and potentiodynamic polarization measurement then the result of these analyses was compared to the result of the dipped mild steel sample in the 0. 1 M HCl solution without inhibitor. The morphology of the mild steel surface immersed in the extract solutions was evaluated by scanning electron microscopy (FE-SEM). According to the EIS results, the significant increment was observed in corrosion inhibition of acidic solution containing SPE in comparison with Blank solution. The result of potentiodynamic polarization measurement showed this green inhibitor acted as a mixed type inhibitor. J. Color Sci. Tech. 13(2020), 331-340© . Institute for Color Science and Technology.

In this paper, the graphene oxide nanosheets modified by benzimidazole were used as the epoxy coating reinforcing nanoparticles. In this way, after synthesizing of graphene oxide and physically adsorption of benzimidazole molecules on them, the modified graphene oxide nanosheets and the unmodified graphene oxide were dispersed in the epoxy matrix. The physical-mechanical properties of the coatings obtained were evaluated by DMTA and tensile tests. In addition, by a scanning electron microscope (SEM) the coating fractured surface morphology and the degree of nanoparticle dispersion in the coatings were studied. The results showed that the benzimidazole molecules could successfully modify the graphene oxide nanosheets surface via noncovalent bonds. Furthermore, the ultimate tensile strength, Young's modulus, strain at break, and energy at break were increased 81%, 15%, 310%, and 207%, respectively, compared to the neat epoxy coating. This improvement in physical-mechanical properties of the coating may be attributed to the better dispersion of the nanosheets in the coating as well as the stronger interactions between the nanosheets and the epoxy resin. J. Color Sci. Tech. 13(2020), 341-352© . Institute for Color Science and Technology.