Dyeing recycled cotton fibers using curcuma longa and pterocarpus santalinus natural dyes and bio-mordant chitosan

Abstract

Problems such as the depletion of natural resources and the increase in environmental pollution brought about by industrialization, the concept of recycling gained great importance. Natural dyes have gained importance again with the increase in environmental awareness. For this purpose, the dyeability of recycled cotton yarns with natural dyes was examined in order to both protect natural resources and reduce the waste water load in dyeing. The paper also discussed a comparison between different ways to mordant cotton with different molecular weight chitosan. Although it was seen by FTIR analysis that cotton fibers were dyed, the presence of chitosan could not be clearly seen. It was explained by the use of low amounts of chitosan. It was observed that the mordanting processes performed with chitosan contributed to the increase in the color strengths, and higher color depths were obtained with the increasing chitosan concentration. Simultaneous mordanting in Curcuma longa dyeing, mordanting before Sandalwood dyeing provided higher color depths than others. The washing fastness of the samples dyed with Curcuma longa revealed the necessity of fastness improvement processes. It was concluded that chitosan mordanting process was effective in terms of sustainable natural dyeing, but it was necessary to improve fastness.