Dyneema®: Super fiber produced by the gel spinning of a flexible polymer

Dyneema® is the ultrahigh molecular weight polyethylene (UHMWPE) fiber showing the higher tensile strength than that of aramid fibers. In addition to the extremely high tensile properties, the fiber shows other unique characteristics, for example, lightweight, chemical stability, shock absorption, negative thermal expansion, etc., and its application area has been widely spread by the long-continued efforts of TOYOBO company and DSM company from the late 1980s. The UHMWPE fibers are manufactured by a unique spinning technology, i.e., gel-spinning method, invented by researchers in DSM in the early 1980s, and this method can be defined as an innovation leading to the industrialization of the super fiber made of flexible chain polymers. In this chapter, the essence of the gel-spinning technology, the structure evolution in the spinning and the drawing process, fiber properties, and applications of Dyneema® are presented. Especially, the reasons, why we can achieve the superior mechanical properties of the UHMWPE fibers with the gel-spinning method, are described by focusing on the microstructures of the fibers.