Kevlar R&D: An Oral History

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.

Interviews and summaries by John Kenly Smith, PhD. Video production by Mike Oates and 302 Stories, Inc. Special thanks to the 1916 Foundation, the friends and family of Mary Laird Silvia, and individual donors for support of this project.

For information on the extensive archival materials related to Kevlar in the Hagley Museum & Library collections, please refer to the online catalog at hagley.org/library.

Herbert Blades

Herbert Blades made important contributions to two major DuPont innovations: Tyvek and Kevlar. After paper-like fibers were made accidentally from high density polyethylene, Blades figured out a polymerization process to make them reliably. For this work he was co-inventor on the patent for Tyvek non-woven sheeting which has many uses, especially in building construction. For the Kelvar development, Blades developed a commercially viable process to spin fibers from the polymer.

His innovative process had three components. First, he discovered that a relatively high concentration of polymer could be dissolved in 100% sulfuric acid if the solution was heated. (100% sulfuric acid has no water in it and is not a corrosive acid). The resulting solution had a low enough viscosity that it could be spun rapidly through a small hole (spinnerette). 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.