Opinião de especialistas em biologia ambiental

Characterization of Cotton Fabric Dyed with Natural Dye Extracted from Old Fustic Wood

Iuliana Dumitrescu, Elena-Cornelia Mitran, Elena Varzaru, Rodica Constatinescu, Ovidiu George Iordache, Dana Stefanescu, Mariana Pislaru and Iulian Mancasi

Knitted cotton fabric was mordanted with mimosa tannin and alum and dyed with Fustic Color. The highest exhaustion degree of the fustic dyebath (29.62%) is shown by the fabric mordanted with 8% mimosa/15% alum followed by 2% mimosa/4% alum. The fastness properties of dyed fabrics to washing, alkaline and acid sweat, dry and wet rubbing and light are poor no matter the type or concentration of the mordants. The poor fastness properties of dyed fabrics could be attributed to the low affinity of the negatively charged cotton fibers for polyphenolic compounds of natural dyes and large molecules of condensed tannins. The vanillin-H2SO4 method demonstrates the presence of large amount of fustic color and tannins in the dyebaths remained after dyeing. The mordanted and dyed fabrics provide an excellent protection against UV rays, the UPF values exceeding 50+. The fabrics mordanted with 2% Mimosa/ 4% Alum and with 8% Mimosa/ 15% Alum and dyed with Fustic Color show a good antibacterial activity against S. aureus.