Finding the Additives Incorporation Moment in Hybrid Natural Pigments Synthesis to Improve Bioresin Properties

Interest in applications of natural dye applications has increased because of their antibacterial properties and the possibility of extracting them from nature and residues. Using nanoclays as hosts to reinforce natural dye properties has been successfully demonstrated. However, no one has attempted to optimize the polymer matrix and hybrid pigment properties at the same time to ensure the best final properties for bio-composite applications. Using a statistical design for experiments, we propose the best combination of modifiers with the best nanoclay as the host of three natural dyes: chlorophyll, β-carotene, and betanine. Using the L9 Taguchi designs, we learned both the influence of the nanoclay structure, and the addition moment of surfactant, mordant salt, and silane modifiers. FTIR, XRD, DTG, integration sphere spectrophotometer, and UV-aging tests were used to characterize the hybrid pigments and epoxy bioresin composites. The degradation temperatures of the three natural dyes rose and the reinforcement of the stability of three natural dyes to UV–Vis radiation exposure was demonstrated, which avoided the migration of these dyes from bioresin to wet ribbing. Optimal results were obtained with hydrotalcite clay (calcined or not) by using surfactant and mordant before the natural dye, and before or after silane.

Chemical Modifications for Intensity Variation and Spectrum Extension of Brazilein Extract from Sappanwood (Caesalpinia sappan L.)

Aqueous extract of sappanwood (Caesalpinia sappan L.) was treated using acid-base and mordant additions in order to expand the intensity and spectra of the colors. The colorant molecule of sappanwood was brazilein, which gained its color characteristics through its double bonds. The results of this study confirmed three basic mechanisms which formed the fundamental for systematic optimization of natural dye applications. Acid addition induced protonation of the hydroxyl groups in the brazilein structure so that the electrons were distributed in the molecule more evenly. Therefore, the color intensity was reduced. Basic treatment created deprotonation of the hydroxyl groups and hence localized the electron on several spots. This made the color of the extract shifted to deeper tones. The addition of mordant created more significant change in color spectrum through the mechanism of chelation to form coordinated complexes. Transitional metals from group 1 and 2 did not chelate strongly so that the spectrum shift was not very obvious. However, transitional metals from group 3 had strong chelating character and consequently they could strongly bind the dye molecules to increase its intensity and shift the spectrum towards deeper colors.

Dyes & Fluorochromes as Imaging Agents in Biology and Medicine - New Opportunities for Dyestuff and Textile Chemists

Dyes and fluorochromes are used in biology and medicine to generate informative microscopic and macroscopic images. This means that the presence, location, biological structure, chemical content and physiological function of cells, tissues and whole creatures can be investigated. A wide range of dyes, both textile and functional, are used in this way. It is suggested that the various groups of stakeholders involved in this approach-end-users in biomedicine; synthesizers, manufacturers & vendors of dyes; and regulators and standardizers-have much to gain by becoming significantly better connected with each other. Broadly speaking, textile dyers use colorants to make socks and shirts and ties more visually attractive, which is not an objective of professional concern to biologists or clinicians. Biomedical applications of colorants are commonly aimed at obtaining information about living systems, using imaging technologies. There are also non-imaging dye applications in which they are used as drugs or analytical reagents, but these are not considered here. Note: below, “dyes” often implies fluorochromes, whilst “biomedicine” is short for biology and medicine.