November 2025 in “International Journal of Biological Macromolecules” This study introduced an eco-friendly enzymatic hair dyeing process utilizing laccase-catalyzed polymerization of hematoxylin, achieving intense, long-lasting color comparable to commercial dyes while enhancing hair strength and offering antioxidant and UV-shielding benefits.
6 citations
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October 2003 in “Journal of applied polymer science” This study found that using poly(ethylene imine) as a counterion reagent improved the colorability and shampoo fastness of bleached human hair when dyed with an acid dye.
5 citations
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January 2004 in “Journal of applied polymer science” This study found that adding urea to a polyethyleneimine solution improved the coloring ability and color fastness of low-temperature hair dyeing with acid dye by enhancing dye penetration into the hair.
December 2025 in “Sustainable Chemistry One World” In this study, researchers found that mangosteen pericarp extract, combined with FeSO₄ as a mordant, effectively produced a stable reddish hair dye on bleached hair, with good color persistence and enhanced tensile strength, indicating its potential as an eco-friendly and safer alternative to synthetic dyes.
September 2011 in “Daehan miyong hakoeji” Henna orange powder, especially with alkali, protects and colors hair better than oxidizing colorants.