Thesis Details


Thesis Title: The effects of fiber crimp, modification ration, and molecular orientation on carpet yarn bulk
Thesis Author: Allen Miller
Abstract: Carpet fibers are manufactured by the fiber producer to possess physical properties that affect the aesthetics and performance of carpet. After the fibers have been purchased by the yarn manufacturer, they are spun into yarn, usually two or more ends twisted together, and heatset. During the heatset process, the assembly of fibers are bulked and set in the desired size or shape such that the assembly resists change to a different size or shape. The process can be carried out in the presence (Superba or autoclave) or the absence (Suessen) of moisture. Most previous research has concentrated on the variation in yarn properties produced by varying machine parameters. However, the exact combination of fiber properties engineered by the fiber manufacturer that increases final yarn is not known. Nylon 6,6 fibers with two modification ratios, two draw ratio, and three crimp levels were used to create 30 yarn conditions. The thirty yarn conditions were spun into yarn and heatset on a Superba TVP to determine the effects of the fiber variants on yarn bulk. Bulk was measured on the 30 yarn conditions using the Textured Yarn Tester (T.Y.T.), Cylinder Bulk Test, and Carpet Body Ranking. Sliver and yarn quality were evaluated using Uster CV, RotorRing, Fiber Alignment Index, Digimat Defects, and Zweigle Hairiness tests. other tests included diagnostic dyeing, X-ray analysis, Differential Scanning Calorimetry, and the Monsanto 20K Contract Walk wear tests. Testing results indicated that the 2.75 modification ratio, 3.75 draw ratio, and 11 c.p.i. fiber yielded the highest level of yarn bulk after heatsetting. Dye uptake was found to increase as the modification ratio increased. The 2.10 modification ratio produced yarn with the best wear characteristics in tufted carpet.