Automotive investments: 1914

In 1914, Pierre S. du Pont invested in the fledgling automobile industry, buying stock in General Motors (GM). The following year he was invited to sit on GM's board of directors and would eventually be appointed the company's chairman. The DuPont company would assist the struggling automobile company further with a $25 million purchase of GM stock. In 1920, Pierre S. du Pont was elected president of General Motors. Under du Pont's guidance, GM became the number one automobile company in the world. However, in 1957, because of DuPont's influence within GM, further action under the Clayton Antitrust Act forced DuPont to divest its shares of General Motors.

Major breakthroughs: 1920s–1930s

A marker outside DuPont's Belle Plant in Dupont City, West Virginia, where ammonia was first synthesized for commercial use.

DuPont's Orlon plant in Camden, South Carolina, c. 1930–1945

In the 1920s, DuPont continued its emphasis on materials science, hiring Wallace Carothers to work on polymers in 1928. Carothers invented neoprene, a synthetic rubber;^[9] the first polyester superpolymer; and, in 1935, nylon. The invention of Teflon followed a few years later. DuPont introduced phenothiazine as an insecticide in 1935.^[10]

Second World War: 1941 to 1945

DuPont ranked 15th among United States corporations in the value of wartime production contracts.^[11] As the inventor and manufacturer of nylon, DuPont helped produce the raw materials for parachutes, powder bags,^[12] and tires.^[13]
DuPont also played a major role in the Manhattan Project in 1943, designing, building and operating the Hanford plutonium producing plant in Hanford, Washington. In 1950 DuPont also agreed to build the Savannah River Plant in South Carolina as part of the effort to create a hydrogen bomb.

Space Age developments: 1950 to 1970

After the war, DuPont continued its emphasis on new materials, developing Mylar, Dacron, Orlon, and Lycra in the 1950s, and Tyvek, Nomex, Qiana, Corfam, and Corian in the 1960s. DuPont materials were critical to the success of the Apollo Project of the United States space program.^{[citation needed]}
DuPont has been the key company behind the development of modern body armor. In the Second World War DuPont's ballistic nylon was used by Britain's Royal Air Force to make flak jackets. With the development of Kevlar in the 1960s, DuPont began tests to see if it could resist a lead bullet. This research would ultimately lead to the bullet resistant vests that are the mainstay of police and military units in the industrialized world.^{[citation needed]}