Paul John Flory (June 19, 1910 – September 9, 1985) was an American chemist and Nobel laureate who was known for his work in the field of polymers, or macromolecules.

They had three children together: Susan Springer, Melinda Groom and Paul John Flory, Jr. His first position was at DuPont with Wallace Carothers.

[11] After Carothers' death in 1937, Flory worked for two years at the Basic Research Laboratory located in the University of Cincinnati.

[10] From 1943 to 1948 Flory worked in the polymer research team of the Goodyear Tire and Rubber Company.

After retirement, Flory remained active in the world of chemistry, running research labs both in Stanford, and IBM.

[2] Flory's earliest work in polymer science was in the area of polymerization kinetics at the DuPont Experimental Station.

In condensation polymerization, he challenged the assumption that the reactivity of the end group decreased as the macromolecule grew, and by arguing that the reactivity was independent of the size, he was able to derive the result that the number of chains present decreased with size exponentially.

In addition polymerization, he introduced the important concept of chain transfer to improve the kinetic equations and remove difficulties in understanding the polymer size distribution.

In 1938, after Carothers' death, Flory moved to the Basic Science Research Laboratory at the University of Cincinnati.

In 1943 he left to join the research laboratories of Goodyear as head of a group on polymer fundamentals.

In the Spring of 1948 Peter Debye, then chairman of the chemistry department at Cornell University, invited Flory to give the annual Baker Lectures.

Flory introduced the concept of excluded volume, coined by Werner Kuhn in 1934, to polymers.

It also led to the concept of the theta point, the set of conditions at which an experiment can be conducted that causes the excluded volume effect to be neutralized.

At the theta point, the chain reverts to ideal chain characteristics – the long-range interactions arising from excluded volume are eliminated, allowing the experimenter to more easily measure short-range features such as structural geometry, bond rotation potentials, and steric interactions between near-neighboring groups.