Purpose -The purpose of this work is to investigate the correlation characteristics in mechanical, thermal and optical properties of PMMA-acrylic polyol polymer blends mixed with lawsone natural dye for coating paint application. Design/methodology/approach -Natural brownish dye colorant was extracted from Lawsonia Inermis leaves used as a dye colorant in this paint coating system by using ethanol as the solvent. Poly(methyl methacrylate) (PMMA), blended with acrylic polyol was used as the binder system. The ratio of PMMA to acrylic polyol was varied with PMMA dominance. The dye colorant was fixed at 10 wt percent. Findings -The potential time measurement tests showed that the dye colorant paint system with 10 wt percent of acrylic polyol has the highest coating resistance against electrolyte penetration. The dye colorant paint system with 30 wt percent acrylic polyol performed better in mechanical tests such as cross-hatch and impact resistance. The dye colorant paint system molecular crosslinks were analysed by using the fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy.Research limitations/implications -The ratio of lawsone dye colorant in the polymer blends is found limited to 10 percent. Increasing in the percentage of lawsone dye colorant will cause inhomogeneity in coating paint sample. Originality/value -A new formulation of natural dye colorant paint system with 10 percent wt dye volume concentration of lawsone as pigment was obtained.

2013),"Characterisation of poly(vinyl alcohol) coating mixed with anthocyanin dye extracted from roselle flower with different nitrate salt", Pigment & Resin Technology, Vol. 42 Iss 2 pp. 146-151 http:// dx.If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The purpose of this paper is to develop a new water based coating system composed of poly(acrylamide-co-acrylic acid) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and characterise the system. Design/methodology/approach -Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted using optimised water extraction method with ratio of calyxes to water being 1:2. UV-Vis absorption spectroscopy was conducted on the anthocyanin extract to monitor its degradation. Poly(acrylamide-co-acrylic acid) was mixed with the extracted anthocyanin solution in two different weight ratios. The mixtures were coated on glass substrate and let to cure for approximately one day. FTIR spectroscopy was conducted on the samples to determine their functional groups and identify the compounds in the samples. Cross hatch test was performed on the samples to determine the adhesion properties. Thermal degradation of the samples was determined through thermogravimetric analysis. Surface roughness of the samples was studied by atomic force microscopy. Colour stability was determined before and after UV irradiation. Findings -Anthocyanin pigment from roselle extracted with water was found to be stable with 6.0 per cent drop in absorbance value over the 15 day period. The reaction rate was found to be 0.000181 h 2 1 , and the half life was calculated to be 3,850 hours. Better adhesion of the samples to the glass substrate was due to the higher concentration of poly(acrylamide-co-acrylic acid). Thermogravimetric analysis revealed similar thermal stability of the samples. Surface roughness study revealed that sample with higher anthocyanin content has higher surface roughness. Colour stability of the 20PBR was found to be better than 10PBR. Research limitations/implications -Usage of poly(acrylamide-co-acrylic acid) as coating is limited by its weak water resistance property. Improvement could be made in this direction for future applications. Practical implications -...

Purpose -The purpose of this paper is to develop a new water-based coating system composed of poly(vinyl alcohol) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and to characterise the system. Design/methodology/approach -Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted by using distilled water and filtered to remove insoluble particle. Salts introduced into the extract were 5wt percent calcium nitrate, 5wt percent magnesium nitrate, and 5wt percent zinc nitrate. The solution was mixed with poly(vinyl alcohol) in ratio of 3:1. The mixtures were coated on glass substrate and allowed to cure for approximately one day. Colour of the extract systems was determined by CIELab colourimetry. FTIR spectroscopy was conducted on the samples to identify their functional groups and changes upon addition of salt. Thermal stability was assessed by thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) was employed to measure the glass transition temperature Tg of the samples. XRD was employed to determine the amorphous properties of the coating samples. Findings -From FTIR spectroscopy, shifting in the OH stretching and CH2 bending bands was attributed to hydrogen bonds formation between PVA and nitrate salt. Shifting in the main decomposition step in samples with addition of nitrate salts in TGA was due to interaction of PVA and nitrate. Increase in glass transition temperature of samples with salts was attributed to the formation of hydrogen bonding. From XRD study, increase in the amorphous properties was due to the incorporation of nitrate salts into PVA coating. Research limitations/implications -Limitation of implementating poly(vinyl alcohol) as coating is caused by its weak water resistance and hydrophilic properties. This study could bring about research towards incorporation of different natural colourant with different binder materials to form coatings which are environmental-friendly and low cost. Practical implications -Mixture of PVA and anthocyanin colourant from roselle for use as coating has been developed. The coating can find usage in various applications such as coloured coating for furniture and wooden materials for decorative purposes, biodegradable design materials for interior purposes. It can be practically applied on a variety of substrates such as glass and wood. Originality/value -Development of water-based coating from PVA binder with anthocyanin colourant is introduced in this study.

Purpose-The purpose of this work is to investigate the influence of curcumin dye natural colorant on adhesion, mechanical, thermal and electrochemical properties of blend poly (methyl methacrylate) (PMMA)-acrylic polyol. Design/methodology/approach-Extracted curcumin yellow dye colorant from Curcuma Demostica was mixed with PMMA-acrylic polyol blended polymer in the volume ratios of 9:1, 8:2 and 7:3. The mixtures were applied on pre-treated cold-roll mild steel panels. All of the paint coating samples were subjected to potential time measurement (PTM), rapid impact deformation, differential scanning calorimetry (DSC), cross hatch and Fourier transform infrared spectroscopy (FTIR) tests. Findings-The addition of curcumin dye colorant was able to improve the adhesion, flexibilities and resistance against electrolytes penetration of the blended poly (methyl methacrylate) (PMMA)-acrylic polyol polymer paint system. Cross hatch test studies showed that high amount of curcumin dye colorant (AP30 paint system) had the lowest peel-off coating area from the substrate. The FTIR test had confirmed the high concentration of hydroxyl group in the AP30 sample. The hydroxyl group was able to promote hydrogen bonding between coating substrate interface. The AP30 sample had the highest coating flexibilities when tested with rapid impact test. This was due to the lowest glass transition value T g which indicated lowest cross linking density in the coating molecules structure. In the PTM test, AP30 paint system had shown the highest rate electrolytes penetration within the AP sample. Research limitations/implications-The composition of curcumin dye colorant in the polymer blend is limited from 10 percent to 30 percent pigment volume concentration. Increasing the amount of lawsone pigment will result inhomogeneous mixtures. Originality/value-The AP paint system is suitable for interior applications. This paint system has to be mixed with suitable additive materials to improve its performance for exterior purpose.

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 ‫ء‬ a ‫ء‬ b ‫ء‬ 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 (⌬E ‫ء‬) 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.