Exploiting Turmeric’s Coloring Capability to Develop a Functional Pigment for Wood Paints: Sustainable Coloring Process of Polyamide 11 Powders and Their Strengthening Performance

Currently, the wood coatings industry is focusing on creating unique, vibrant finishes using new functional pigments. Simultaneously, there is a growing adoption of eco-friendly bio-based materials, reflecting trends in other sectors and supporting the circular economy. Thus, the aim of this study is to unveil a straightforward, cost-effective, and notably sustainable process for exploiting the coloring potential of turmeric powder and coloring polyamide 11-based fillers, employed as multifunctional pigments for wood coatings. Through the incorporation of this additive into a wood paint, the study demonstrates its dual effect of enhancing the aesthetics of the final composite layer while leveraging the beneficial protective properties inherent to polyamide 11. The impact of these additives on sample aesthetics is assessed through optical observations, as well as measurements of color, gloss, and surface roughness. The strengthening contribution of the functional pigment is evaluated using the Taber abrasion resistance test, static friction coefficient measurements, and Buchholz surface hardness test. Finally, the aesthetic consistency of the bio-based filler and the coloring efficiency of the sustainable process are tested by subjecting the samples to aggressive conditions, including the UV-B chamber exposure test, cold liquids resistance tests, and water uptake test. Ultimately, the study illustrates how this functional bio-based pigment not only provides sufficient protection but also meets current eco-requirements, thereby contributing to the sustainability of the wood coatings industry.