Date Approved

2019

Degree Type

Campus Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

College of Technology

Committee Member

Subhas Ghosh, PhD

Committee Member

Deb de Laski-Smith, PhD

Committee Member

Suleiman Ashur, PhD

Committee Member

Gregg Wilmes, PhD

Abstract

This research aimed to more fully understand the effects of natural dyes including tea, pomegranate, and myrobalan on hemp fabric. The basic purpose of this study was to develop a natural dyeing process for natural fibers that improved wash fastness. It focused on the formulation for dyeing with natural colorants, optimization of the dyeing techniques, and development of the best procedure. This research used a full factorial design of experiments to best optimize the dyeing procedure. Independent variables included dye type, mordant type, dye concentration, and mordant application. All samples were laundered for 20 cycles to determine color retention of the dyes. Color trimstimulus values (CIELab) and dye depth values were measured throughout the process. Statistical analysis was done to best explain K/S for the independent variables. Statistical analysis techniques included analysis of variance, significance at 95% confidence, interactions of the independent variables, and trend analysis for color retention. Loss in dye depth and change in color (Delta E) values were calculated to understand the change in color along with a visual analysis. Fourier transform infrared (FTIR) scans were evaluated and transformed to second derivative for hemp fabric before and after dyeing to confirm the presence of the dye on the finished sample. The best dyeing process for three natural dyes: tea, myrobalan, and pomegranate was found to be with alum as the mordant, 20% dye concentration, and pre- or post-mordant application. All three types of dye were found to have a good wash fastness. FTIR scans found subjective evidence of the natural dyes on the hemp fabric after dyeing.

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