Thesis Details

Thesis Title: Effects of sodium hydroxide solution temperature and concentration, and fabric stretch in the mercerization process on dye uptake and physical properties of 100% cotton fabric
Thesis Author: Kistin Rowe
Abstract: As the mercerization process becomes more advanced, textile manufacturers are investing in ranges such as Benninger's new "Dimensa" range. Innovative concepts involving hot mercerization and chain/chainless tension assist these ranges in producing a superior quality product. Thus, in order to optimize the process, it is necessary to understand how each factor affects the end properties of the fabric. This study was designed to examine the effects of caustic concentration, solution temperature, and tension in the mercerization process on the fiber morphology, physical properties, and shade difference of 100% cotton, 3/1 twill fabric. The fabric was mercerized in the laboratory at ITT using a stretching device similar to those used for silk-screening. Additional fabric was mercerized on Benninger's "Dimensa" range. Once mercerized, the fabric was dyed with a direct, vat, sulfur, and fiber reactive dye. The internal structure of the fibers was examined using near-infrared spectrophotometry, x-ray diffraction, and barium activity number determination. Strength testing and fiber cross-section evaluation were used to evaluate the physical properties of the fabric. Finally, reflectance, absorbance, and luster measurements were taken of the dyed fabric. Test results showed that the chemical concentration of the caustic sod:a significantly effected a variety of fabric properties. Not only did the degree of mercerization increase with higher concentrations, but the tensile strength, fiber diameter, dye uptake, and whiteness were also significantly effected. Furthermore, higher levels of tension caused an increase BAN and luster. Finally, fiber cross-section was affected by an interaction betwee:n tension and temperature, and dye uptake was affected by an interaction between tension and chemical concentration. Approximately 75-80% of the differences in shade can be attributed to dye uptake, while the other 20% is the result of luster, gloss, and whiteness. In conclusion, barium activity numbers can be used to predict changes in the crystalline order, crystalline index, and lattice structure of the fabric.