Abstract
The dyeing characteristics of fibers from three Acala cotton varieties, i.e., Maxxa, SJ-2, and SJC-9, are investigated using direct and reactive dyestuffs along with the Goldthwait cotton maturity test. Dyed and less-dyed fibers are detached from the dyed seed fibers, separated, and characterized by seed fiber weight, single fiber strength, and color measurement. With Direct Blue 1, SJC-9 fibers are dyed to the darkest shade across all seed fiber weights, whereas the Maxxa fibers have the lightest shade. The SJC-9 seed fibers have the least amounts ( ~5%) of less-dyed fibers and the proportions of such fibers are independent of seed fiber weights. For the Maxxa and SJ-2 varieties, the proportions of less-dyed fibers decrease with increasing seed fiber weights. The proportions of less-dyed Maxxa and SJ-2 fibers are above 30% on seed fibers weighing less than 100 mg and are 10% or less on seeds weighing more than 150 mg. The SJ- 2 seed fibers contain higher proportions of less-dyed fibers, but their overall shades are deeper than the Maxxa fibers. For all three varieties, most less-dyed fibers are from the chalazal ends of the seeds of all seed fiber weights. Dyeing with Reactive Blue 19 results in the same proportions of less-dyed fibers on the Maxxa seed fibers as with Direct Blue 1. The Goldthwait cotton maturity test confirms the trend of decreasing amounts of less-dyed fibers with increasing seed fiber weight with both direct and reactive dyes. For all three varieties, the force to break is higher for the dyed fibers than the less-dyed fibers, confirming that less-dyed fibers have less developed cell wall structures.