Tensile properties of various cotton and Dyneema® blend yarns

Abstract

376-380A series of ring- and rotor-spun yarns has been produced from the low-level blends of Dyneema®, a gel-spun ultra-high molecular weight, high-density polyethylene fiber (HDPE) of varied types, with selected white and naturally colored cottons and the tensile properties of blended yarns studied. The Dyneema® fiber is commonly referred to as high performance polyethylene (HPPE) due to its exceptionally high strength. The addition of small quantities of certain HPPE fibers substantially increases the yarn tenacity and breaking elongation of certain cotton blended yarns, particularly those made from naturally colored cottons. The resultant yarn tenacity appears to be influenced by the fineness of the constituent fibers and the level of yarn twist. The effect is more pronounced for the colored cottons than for the H PPE blends with white cotton. Whereas the yarn strength tends to increase for the pure brown and white cottons as the twist increases, it decreases in the green cotton yarns with the increase in twist within the range studied. However, the addition of small quantities of HPPE fiber results in substantial increase in tenacity for all at a constant level of twist. Finer HPPE fibers provide a greater improvement in yarn strength as compared to coarser HPPE fibers. The different frictional properties and geometries of the constituent cottons and synthetic fibers play a role in their blending and associated resultant yarn strength. The use of small quantities of l-denier HPPE fiber significantly increases the strength and elongation of cotton blended yarns, particularly those made from brown cotton, with the minimal change in observed color. Such cotton and Dyneema® blends may find application in special purpose denims, where pure cotton yarns (whether white or naturally colored) or the traditional cotton-rich blends with conventional synthetics may not meet the performance requirements for fabric strength