A combination of three surface modifiers for the optimal generation and application of natural hybrid nanopigments in a biodegradable resin

Abstract

Our purpose was to improve the thermal, mechanical, and optimal properties of an epoxy bioresin using optimum hybrid natural pigments previously synthetized in our lab. Then, we searched the best combinations of factors in the synthesis of natural hybrid nanopigments, and then incorporated them into the bioresin. We combined three structural modifiers in the nanopigment synthesis, surfactant, coupling agent (silane) and a mordant salt (alum), selected to replicate mordant textile dyeing with natural dyes.We used Taguchi's design L8 to seek final performance optimisation. We selected three natural dyes, chlorophyll, beta-carotene and beetroot extract, and used two laminar nanoclay types, montmorillonite, and hydrotalcite. The thermal, mechanical and colorimetric characterisation of the composite obtained by mixing natural hybrid nanopigments (bionanocomposite) was made. The natural dye interactions with both nanoclays improved the natural dyes and bioresin's thermal stabilities, colour performance and UV-VIS light exposure stability. The best bionanocomposite materials were found by using an acidic pH [3][4] environment, and modifying nanoclays with mordant and surfactant during the nanopigment synthesis process.

Stabilized Dye–Pigment Formulations with Platy and Tubular Nanoclays

“…The migration for each natural dye was avoided due to different lamellar nanoclays ( Figure a). Natural dye incorporation as hybrid pigments using lamellar nanoclays increases their industrial application possibilities …”

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

“…It is well known that the adsorption process is dependent on the natural dye structure used [37]. LD presents anionic characteristics [8] and the ability of HT to host anionic dyes has been reported by other authors.…”

“…Different modifiers (surfactant, coupling agent (silane) and a mordant salt (alum)) were combined to improve the natural dyes adsorption. The results demonstrated an improvement in thermal stability, color performance and UV-VIS light exposure stability for the obtained bionanocomposites [37].…”

“…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].…”