Comparison study on the effect of acid and nitrate salt on the properties of poly(vinyl alcohol) coating doped with dye consist of anthocyanin

2015 ◽  
Vol 44 (4) ◽  
pp. 250-256
Author(s):  
S.V. Lee ◽  
R. Usop ◽  
A.N. Hadi ◽  
N.A. Mazni ◽  
S.R. Majid ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrochloric Acid ◽  
Calcium Nitrate ◽  
Natural Dye ◽  
Poly Vinyl Alcohol ◽  
Nitrate Salt ◽  
Comparison Study ◽  
Coating Films ◽  
Content Type ◽  
Thermal Stability Of

Purpose – The purpose of this paper is to observe the thermal and colour stabilities of coating films consisting of natural dye anthocyanin colourant with acid and nitrate salt as additives. Design/methodology/approach – The natural dye was extracted from Hibiscus sabdariffa L. (Roselle) by using distilled water as solvent. The extracted dye was mixed with 1 weight per cent hydrochloric acid and 5 weight per cent calcium nitrate to conduct the comparison study. The dye samples were than mixed with poly (vinyl alcohol) (PVA). The mixtures were applied on glass panels to form coating films. The coating films were left to dry for 24 hours. The thermal stability of coating films was investigated by using thermogravimetric analysis (TGA). The amorphousness coating films molecular structures were observed by using x-ray diffraction (XRD). CIE L*a*b* colour coordinate space technique was used to investigate the coating films colour stability against ultraviolet (UV). Findings – The results show that addition of hydrochloric acid (HCl acid) enhanced thermal stability of PVA-anthocyanin coating and shifted the degradation temperature to higher temperature at 300°C. HCl acid also improved UV stability of the coating system significantly with the reduced ΔE from 26.67 to 16.89. Addition of calcium nitrate (Ca(NO3)2) salt promotes good interaction with PVA-anthocyanin system that caused structural changes, improved thermal stability and increased Tg from 61.5 to 83.1°C. Research limitations/implications – The potential of using natural dye extracted from plant as renewable material. Practical implications – The coating films developed in this works are suitable for glass substrate application. Originality/value – Development of water-based coating from PVA binder with anthocyanin colourant is introduced in this study.

Thermal and UV degradation of roselle anthocyanin extract and its mixtures with poly(vinyl alcohol) in different acid

2015 ◽  
Vol 44 (2) ◽  
pp. 109-115 ◽  
Author(s):  
S.V. Lee ◽  
A.N. Hadi ◽  
Z.H.Z. Zainal Abidin ◽  
N.A. Mazni ◽  
N.A. Halim ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Glass Substrate ◽  
Half Life ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Colour Stability ◽  
Coating Films ◽  
Content Type ◽  
Red Dye

Purpose – The purpose of this paper is to observe the colour and thermal stability of natural red dye consisting of anthocyanin with addition of different aqueous acids and applied as coating films. Design/methodology/approach – The natural red dye was extracted from Hibiscus sabdariffa L. (roselle) flowers and mixed with 1 per cent hydrochloric acid, 5 per cent acetic acid, 5 per cent citric acid and 5 per cent oxalic acid. All the dye samples were exposed to heat and UV-B to observe the colour stability by calculating the half-life and rate of reaction. In coating film application, each of the dye samples was mixed with 25 wt% of poly(vinyl alcohol) (PVA) and applied on to a glass substrate. The coating samples’ colour stability was observed by using CIE L*a*b* colour space coordinates. The coating films’ weight loss stability against temperature was observed by using thermogravimetric analysis. Findings – Addition of hydrochloric acid enhances the thermal and UV stability of the anthocyanin natural dye. This can be observed from the calculation of the half-life of the dye. The half-life values for the thermal and UV stability studies were 1,155 hours and 210 hours, respectively. In coating films, the sample with addition of acetic acid showed the highest colour stability with colour difference (ΔE*) value 8.95. Research limitations/implications – The coating films developed in this work are not suitable to be applied on metal substrates due to the presence of water, which can contribute to the corrosion formation. Practical implications – The coating films developed in this work are suitable for washable coating application. In other words, they are non-permanent coatings applied on a glass substrate. Originality/value – Development of water-based coatings from PVA binder with anthocyanin colourant is introduced in this study.

The supercooling ability of calcium nitrate solutions in ethylene glycol

1989 ◽  
Vol 54 (10) ◽  
pp. 2711-2714
Author(s):  
Ivo Sláma ◽  
Jarmila Malá
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Induction Period ◽  
Calcium Nitrate ◽  
Transformation Diagram ◽  
Temperature Transformation ◽  
Thermal Stability Of ◽  
Nitrate Solutions

The dependence of the induction period of crystallization on the supercooling was determined for the Ca(NO3)2-ethylene glycol system at mole fractions of the former from 0 to 0.049, and treated in terms of the TTT (Time-Temperature-Transformation) diagram. Addition of Ca(NO3)2 to ethylene glycol brings about a substantial increase in the critical induction period of crystallization. The thermal stability of glasses is discussed in terms of the shape and position of the TTT curves.

Preparation and Thermal Properties of High-Purified Molten Nitrate Salt Materials with Heat Transfer and Storage

2015 ◽  
Vol 34 (8) ◽  
Author(s):  
Hongtao Zhang ◽  
Youjing Zhao ◽  
Jingli Li ◽  
Lijie Shi ◽  
Min Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Molten Salts ◽  
Operating Temperature ◽  
Nitrate Salt ◽  
Solar Salt ◽  
And Storage ◽  
Thermal Stability Of ◽  
Operating Temperature Range

AbstractThis paper focuses on thermal stability of molten salts, operating temperature range and latent heat of molten salts at a high temperature. In this experiment, multi-component molten salts (purified Solar Salt) composed of purified NaNO

scholarly journals Kinetic models of swelling and thermal stability of silver/poly(vinyl alcohol)/chitosan/graphene hydrogels

2019 ◽  
Vol 77 ◽  
pp. 83-96 ◽  
Author(s):  
Katarina Nešović ◽  
Ana Janković ◽  
Aleksandra Perić-Grujić ◽  
Maja Vukašinović-Sekulić ◽  
Tamara Radetić ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Kinetic Models ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Thermal Stability Of

Theoretical analysis and experimental study on thermal stability of high-speed motorized spindle

2017 ◽  
Vol 69 (6) ◽  
pp. 1049-1065 ◽  
Author(s):  
Zhe Liu ◽  
Wei Chen ◽  
Desheng Li ◽  
Wenjing Zhang
Keyword(s):  
Thermal Stability ◽  
Experimental Study ◽  
Theoretical Analysis ◽  
High Speed ◽  
Thermal Deformation ◽  
Motorized Spindle ◽  
Content Type ◽  
Front End ◽  
Temperature Distributions ◽  
Thermal Stability Of

Purpose In high-speed processing, the influence on the machining accuracy of a machine tool is greatly caused by the thermal deformation of the motorized spindle; a further study on the thermal characteristics of the spindle is given in this paper. This study aims to reduce the thermal error and improve the performance of the machine tool by discussing the relationships between the temperature distributions and rotating accuracy caused by the thermal deformations of the spindle. Design/methodology/approach The paper opted for a method combining the theoretical analysis and the experimental study to study the thermal stability of the high-speed motorized spindle. First of all, a finite element model of the spindle was built with ANSYS, whereby temperature distributions and the thermal deformations were successively obtained at different speeds. And then, both the temperature field and the rotating accuracy of the motorized spindle were measured simultaneously by the thermal stability experiment. Finally, the experimental and theoretical results were compared and validated. Findings The thermal stability of the motorized spindle was studied in this paper, and some findings from the study were as follows: the spindle’s rotating accuracy maintained good in X direction but bad in Y and Z directions in terms of the deformations; the higher front-end temperature of the spindle which can significantly affect the rotating accuracy is needed to be controlled mainly; the recovery speed of the spindle deformation lagged behind the temperature’s fallback speed; the vibration graph about radial rotating sensitivity synthesized by X1 and X2 presented a trifoliate shape. Originality/value Based on a built test-bed which can synchronously measure the motorized spindle’s temperature distribution and rotating accuracy with five-point method, the coupling effects of the thermal deformation and temperature are embodied, and not only the vibration graph but also the thermal tilt angles can be gained. Therefore, considering the influence of the thermal deformation on the heat generated by the bearings, the paper fulfilled a study by which it was obtained that the front-end temperature of the spindle, which was higher and could significantly affect the rotating accuracy, needed to be controlled mainly.

The properties of sericin/poly(vinyl alcohol) films modified by boric acid

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Qun Wang ◽  
Lu Qi
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Boric Acid ◽  
Vinyl Alcohol ◽  
Water Resistance ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Blend Ratio ◽  
Percutaneous Drug Delivery ◽  
Thermal Stability Of

AbstractA group of films mainly composed of sericin and poly(vinyl alcohol) (PVA), using boric acid (BA) as a modifier, were prepared by a technique of solution casting. In this work, the effect of BA and sericin on the mechanical properties and water resistance of the films was analyzed, the interior morphology of the films were described by a scanning electron microscopy (SEM), the thermal stability of the films was characterized by differential scanning calorimetry (DSC), and the reaction mechanism was proposed according to the previous literature and the test of Fourier transform infrared spectrum (FTIR). Results indicated that, the properties of the membrane were the functions of the blend ratio of sercin to PVA and the content of BA. The use of BA increased the tensile strength, improved the water resistance and the thermal stability, and varied the interior morphology of the films. The content of sericin greatly influenced the combination of properties of the films, especially the mechanical properties, interior morphology, thermal stability, and water resistance reducing with the increasing of sericin content. The films have potential to be used in materials, such as skin-care coatings for beauty, percutaneous drug delivery systems for exterior intact skin, due to the characteristics of the components and the good mechanical properties of the films.

scholarly journals The Synthesis Process and Thermal Stability of V2C MXene

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2112 ◽  
Author(s):  
Meng Wu ◽  
Bingxin Wang ◽  
Qianku Hu ◽  
Libo Wang ◽  
Aiguo Zhou
Keyword(s):  
Thermal Stability ◽  
Hydrochloric Acid ◽  
Vanadium Carbide ◽  
Potassium Fluoride ◽  
Synthesis Process ◽  
Three Solutions ◽  
Etching Solution ◽  
Air Atmosphere ◽  
Vanadium Trioxide ◽  
Thermal Stability Of

The effect of etching solution on the synthesis process of two-dimensional vanadium carbide (V2C MXene) was researched. Three etching solutions were used to etch ternary carbide V2AlC at 90 °C. The three solutions were: lithium fluoride + hydrochloric acid (LiF + HCl), sodium fluoride + hydrochloric acid (LiF + HCl), and potassium fluoride + hydrochloric acid (KF + HCl). It was found that only NaF + HCl solution was effective for synthesizing highly pure V2C MXene. The existence of sodium (Na+) and chloridion (Cl−) in etching solution was essential for the synthesis. The thermal stability of the as-prepared V2C MXene in argon or air was studied. From thermogravimetry and differential thermal analysis, V2C MXene was found to be stable in argon atmosphere at a temperature of up to 375 °C. As the temperature increased, V2C MXene was gradually oxidized to form nanoparticles composed of vanadium trioxide (V2O3) and a part of V2C MXene was broken and transformed to vanadium carbide (V8C7) at 1000 °C. In air atmosphere, V2C MXene was stable at 150 °C. At 1000 °C, V2C MXene was oxidized to form vanadium pentoxide (V2O5).

The colour stability of natural dye coating films consisting of chlorophyll after exposed to UV-A

2016 ◽  
Vol 45 (3) ◽  
pp. 149-157 ◽  
Author(s):  
R. Usop ◽  
Z.H.Z Abidin ◽  
N.A. Mazni ◽  
A.N. Hadi ◽  
N.A. Halim ◽  
...  
Keyword(s):  
Natural Dye ◽  
Coating Film ◽  
Colour Stability ◽  
Coating Films ◽  
Content Type ◽  
Cassia Alata ◽  
Glass Substrates ◽  
Blended Polymer ◽  
Effect Of Copper ◽  
Colour Coordinates

Purpose This paper aims to study the colour stability of chlorophyll and the effect of copper (II) nitrate – Cu(NO3)2 – as an additive in natural dye coating films after being exposed to ultraviolet-A (UV-A). Design/methodology/approach The natural dye was extracted from the leaves of Cassia alata L. using absolute ethanol as the solvent. The extract was divided into two parts and, one of it was added with 3 wt.% Cu(NO3)2 as an additive. The polymer blend of poly(methyl methacrylate) (PMMA) and acrylic polyol was used as the coating binder. Both parts of the dye with and without additive were mixed with the blended polymer in a specific ratio. The resulted mixtures were applied as coating films on glass substrates. The colour stability of the coating films on exposure to UV-A with the time of exposure was observed with Commission internationale de l’éclairage (CIE) L*a*b* colour coordinates. The hidden power by the means of reflectivity and glossiness of the coatings was also studied. Statistical standard deviation (STD) was used to analyse the data. Findings The test showed that the coating films containing Cu(NO3)2 had smaller colour differences, (ΔE*) indicating higher colour stability. The analysis on hidden power also showed that the coating film with Cu(NO3)2 was 1.6 times more stable than the film without additive. All the measurements in this study were observed within 35 days of duration. Research limitations/implications This paper implies the potential of using natural dye extracted from Cassia alata L. leaves as a stable dye colourant for coating applications. Practical implications The coating film developed in this study is suitable for glass substrate applications. Originality/value A new method of preparing solvent-based coating film from PMMA–acrylic polyol with chlorophyll colourant is introduced in this study.

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