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

Abstract

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.

Effect of Lemon Waste Natural Dye and Essential Oil Loaded into Laminar Nanoclays on Thermomechanical and Color Properties of Polyester Based Bionanocomposites

“…For the synthesis of the lemon hybrid dye-nanoclay systems, the water/organic solvent dispersion method was followed, based on previous research [4,37]. The best synthesis conditions to maximize lemon dye adsorption were studied by using a 2 4−1 fractional factorial design of experiments (DoE) using 50% (v/v) ethanol as solvent.…”

“…The presence of surfactant, mordant and silane modifiers allowed LD adsorption in both nanoclays, due to nanoclay interlayer and surface modifications [37]. Sheet clay polarity has also been reported to influence the encapsulation of the organic dye [4]. Surface modifiers such as surfactants or silane-coupling agents are needed to modify the nanoclay surface polarity.…”

“…Ecological concerns related to the use of synthetic dyes have motivated industries to consider the replacement of these compounds by eco-friendly non-toxic natural dyes to minimize the negative environmental impact and health hazardous problems related to cytotoxicity, genotoxicity, and carcinogenicity of synthetic dyes [1][2][3]. Natural dyes and pigments have been also used as polymer additives due to their antimicrobial, antioxidant or deodorant properties [4].…”

“…Lemon dyes are widely used for coloring and medicine [8]. However, natural dyes could present several drawbacks such as low light fastness, difficult color reproduction between different natural dye samples, limited color range, poor color fastness and reduced chemical and thermal stability [4,9,10]. Regarding essential oils (EOs), they have been also considered as functional additives in food packaging and cosmetic sectors due to their antibiotic and flavoring properties [11].…”

“…Depending on the nanoclay exchange capacity, some surface modifications should be needed, such as the use of surfactants [17][18][19] or silane couple agents to open the nanoclays structure and improve their adsorption capacity. Additionally, it has been proved that other additives used with natural dyes, such as mordant salts, can improve the natural dye-nanoclay interactions [4]. In another approach, Guillermin et al [20] developed hybrid materials based on montmorillonite, polydiallyldimethylammonium chloride, as cationic polymer, and carminic acid.…”