Wood Extracts for Dyeing of Cotton Fabrics—Special View on Mordanting Procedures

Abstract

Natural dyes offer a bio-based opportunity to support the attractive coloration of textile fabrics made from natural fibers like cotton, wool, hemp, and many other textile materials. They can be part of a strategy to realize fully bio-based textiles and clothing materials. In line with this statement, the following study investigates the use of wood extracts for dyeing cotton fabrics. Specifically, extract powders of logwood (Haematoxylon campechianum L.), brazilwood (Caesalpinia spp.), and quebracho wood (Schinopsis lorentzii) are used. The aim of the study is to evaluate which colorations can be obtained by the application of those wood extracts and what fastness properties are reached. For this, different modified process parameters and mordants are evaluated. The dyeing process is modified using different mordants based on iron and aluminum salts. These mordants are applied in pre-, meta-, or post-mordant procedures. The color and fastness properties of prepared textile samples are determined by spectroscopic measurements, color measurements, washing procedures, and a Xenotest for measuring the light fastness. Ultimately, it is shown that a broad range of colorations can be realized through different combinations of wood extracts and mordanting procedures. Notably, stronger color depths are reached with pre- and meta-mordanting compared to post-mordanting. Good wash fastness is obtained for some color shades. However, with post-mordanting, better wash fastness can be achieved. The light fastness of the realized samples is only moderate to low. In conclusion, it can be stated that dyes from wood extracts are excellent materials to dye natural fibers if they are combined with the right mordanting agent in pre- or meta-mordanting procedures. The present study is therefore a good proof-of-concept for the realization of fully bio-based colored textile materials.