Photo of Paul John Flory

Paul John Flory

  • National Medal of Science
  • Physical Sciences

For his outstanding contributions to our understanding of the modes of formation and structure of polymeric substances.

During World War II, rubber – typically sourced from a species of tree – was a vital commodity, used in manufacturing for military vehicles, shoes and other resources.

As Japan conquered southeast Asia, the need to produce synthetic rubber emerged as the world’s largest natural supply, the forests of Thailand and Indonesia, became unavailable to the Allies.

During his years at DuPont, Paul John Flory saved the day, making fundamental contributions that helped scientists better understand polymers like rubber, comprised of long molecules strung together in chains.

In a paper, Flory explained the need to include a step called “chain transfer,” where a polymer chain stops growing by taking an atom from another molecule.

This discovery, which allowed for scientists to control the length of polymer chains, made the mass production of rubber possible during World War II, changing the industry forever. By 1950, the use of synthetic rubber outpaced natural rubber.