In this chapter we describe synthetic polymeric fibers, which saw tremendous advancement in the last half of the twentieth century. In fact, a reasonable case can be made that the so-called age of fibers began with the advent of synthetic fibers such as nylon, polyester, etc. in the late 1930s and early 1940s. Many companies such as DuPont, Monsanto, BASF, Hoechst, ICI, etc. contributed very heavily in this area. For a historical account of the scientific and technological progress made in this area, the reader is referred to a study of research and development activities at DuPont during the period of 1902–1980 (Hounshell and Smith, 1988). Most of these synthetic polymeric fibers such as polyester, nylon, etc. have very uniform and reproducible properties. They have a rather low elastic modulus, however, which restricts them mostly to the apparel or textile market. It was the research work aimed at making strong and stiff synthetic polymeric fibers for use as reinforcements in polymers, which started sometime in the late 1960s, that resulted in the commercial availability of strong and stiff fibers such as aramid and polyethylene. We describe below the processing, structure, and properties of some important synthetic polymeric fibers in some detail.

The age of synthetic polymeric fibers

A brief historical review of the work in the area of organic fibers will be helpful in placing things in perspective. We begin with the discovery of nylon, also known as polyamide (PA). Nylon was discovered and commercialized by DuPont in 1938 (Magat and Morrison, 1976). Wallace Carrothers of DuPont is generally regarded as the father of nylon. Nylon first penetrated the silk hosiery market just before the start of World War II. In fact, 1988 marked the 50th anniversary of the introduction of nylon silk stockings. Nylon is made by melt spinning. It is a very flexible, knittable, and durable fiber; all these attributes have made it one of the most important fibers for the textile industry. Nylon's reasonably high strength, good impact, and fatigue resistance also led to its use in the tire industry. It should be noted that the term nylon is a generic term that represents a group of similar materials, in the same vein as glass, steel, or carbon. Accordingly, we spell it without a capital letter.