History of Kevlar oral history interviews
About this collection
The oral histories presented here document the research and development processes that transformed Kevlar from a novel polymer in the laboratory to a life-changing product in the marketplace. Through many surprising twists and turns, the people profiled here managed to make Kevlar serve the complicated and occasionally contradictory interests of the DuPont company, scientific inquiry, the marketplace, and the general public. Their stories are a rich study in the business and technology of innovation. Click here to view the finding aid for this collection.
- Interviews were conducted by John Kenly Smith, PhD, in 2014 and 2015. Special thanks to the 1916 Foundation, the friends and family of Mary Laird Silvia, and individual donors for support of this project.
- Donald Sturgeon details his work at DuPont evaluating the properties of Kevlar fibers, particularly for their utility in composite structures. He recounts that while the fiber was incredibly strong in tension, it had relatively poor performance in compression. The peculiar features of Kevlar fibers required that Kevlar reinforced products had to be carefully engineered. Initially, DuPont hoped that Kevlar would find a large market as tire cord. When tire manufacturers opted for steel belts in radial tires, DuPont had to find other markets for Kevlar. Sturgeon further describes his work in developing novel applications for Kevlar. Because Kevlar was difficult to make and process, DuPont had invested an unprecedented $500 million by the mid-1970s. Instead of one large market, DuPont had to develop many smaller applications for Kevlar. Sturgeon worked on developing and promoting weight-saving Kevlar composite materials to the aircraft industry. He was also involved in developing bullet-proof vests and non-cut fabrics. Through these extensive product development and marketing efforts, Kevlar eventually became a profitable product.
- Irénée du Pont, Jr., describes his early life and later career with the DuPont Company. After World War II, he joined the DuPont Company where for the next two decades he held a variety of jobs. He describes his time on the DuPont executive committee, which he joined in 1967, during which the company had to deal with increasing competition, social unrest in Wilmington, equal opportunity legislation, and environmental regulation. Among other anecdotes, du Pont describes how his father, along with his brothers Lammot and Pierre, set off large fireworks displays at Fourth of July celebrations in the 1920s. He also remarks that he believes Pierre continued to play an important role in the affairs of the company until his death in 1954.
- After describing his education and early work at the DuPont Company on polymer solutions, Herbert Blades recounts his contributions to the development of Tyvek and Kevlar. On the Tyvek project, he describes developing the polymerization process for creating high-density polyethylene fibers after such paper-like fibers had been accidentally created in the laboratory. Blades details his work on Kevlar, for which he developed a commercially viable process to spin fibers from the polymer. Blades describes the three components of the process. First, he discovered that a relatively high concentration of polymer could be dissolved upon heating in 100 per cent sulfuric acid, which is non-aqueous and non-corrosive. The resulting solution had a low enough viscosity that it could be spun rapidly through a spinnerette, a small hole. Next, Blades discovered that instead of spinning the fiber directly into a water bath, leaving a small air gap led to fibers that were significantly stronger. Finally, he determined that the water "quenching" of the fiber occurred extremely fast. His spinning innovations made it possible to spin Kevlar fibers economically and at high speeds.
- Wesley Memeger, Jr. details his contribution to streamlining the synthesis of Kevlar, which allowed the timely start-up of the first commercial scale Kevlar plant. In the laboratory, the polymer for Kevlar had previously been prepared by polymerizing para-phenylene diamine and terephthaloyl chloride in a mixture of two solvents, HMPA (hexamethylphosphoramide) and NMP (N-methylpyrrolidinone). Memeger found that a polymer with satisfactory molecular weight could be made using only HMPA, a discovery which made the preparation of Kevlar more commercially viable, as it allowed for a continuous polymerizer in a single solvent system. Memeger recounts that DuPont used HMPA as the solvent for Kevlar production in the early 1970s, but after toxicology tests conducted at the company's Haskell Laboratory raised doubts about the safety of the solvent, DuPont replaced HMPA with NMP and calcium chloride. Memeger describes his subsequent work at DuPont investigating melt processible polymers, which share some properties with Kevlar but lack equivalent chemical and thermal stability, as well as his work on ring opening routes to polymers with novel properties. An accomplished artist, Memeger continues to be impressed by the elegance and simplicity of the Kevlar polymer that produces such remarkable properties.
- Bob Wolffe details his contribution to Kevlar, which primarily involved working with the aircraft industry to develop markets for Kevlar fibers in weight-saving composite materials. Wolffe consulted with aircraft engineers to learn their requirements and made composite materials to meet the industry's specifications. The first applications were for interior, non-structural uses where failure would not jeopardize the safe operation of the aircraft. Over time, DuPont developed significant domestic and international markets for Kelvar composites in aircraft. Wolffe notes, though, that the most important application was in ballistics. Wolffe recounts DuPont's efforts during the 1980s to produce its own fabricated composite parts in an effort to move away from being primarily a supplier of Kevlar fabric. Wolffe attributes the failure of this venture to the company underestimating the importance of design and testing of aircraft parts.
- After describing his education and early work at the DuPont Savannah River plant, Merriman describes his first project at the Pioneering Laboratory at DuPont Experimental Station in Wilmington in 1969 working on new uses for ceramic aluminum oxide fiber PRD-29. Merriman then details his role in developing a pulped form of Kevlar fiber that made it suitable for use in automobile brake lining in the late 1970s, after it was discovered that the standard material, asbestos fiber, caused a particular form of lung cancer. Merriman developed a process that produced Kevlar fluff using conventional paper-making equipment. Because Kevlar cost about one hundred times as much as asbestos, brake linings had to be redesigned to use very small amounts of it. Working with brake pad manufacturers, Merriman succeeded in producing a commercially viable Kevlar brake pads that had good wear characteristics and were quieter than other types. Brake lining became a significant market for Kevlar. Merriman also describes the extensive testing on Kevlar that DuPont performed at its toxicology facility, the Haskell Laboratory, to ensure that Kevlar did not have adverse health effects.