5 citations
,
January 2004 in “Journal of applied polymer science” Urea helps hair dye penetrate better and last longer.
6 citations
,
October 2003 in “Journal of applied polymer science” A new method using poly(ethylene imine) improves hair dyeing at lower temperatures with better color retention.
1 citations
,
September 2008 in “International Journal of Cosmetic Science” Using chelants in hair dye reduces fiber damage by preventing harmful radicals.
Hair coloring and bleaching can permanently break down hair protein and temporarily change its properties.
June 2017 in “University of the Arts London Research Online (University of the Arts London)” Polymers help reduce damage and improve bleached hair when used during or after bleaching.