Waldo Semon was born on September 10, 1898, in Demopolis, Alabama. When Semon was seven years old, his family moved to the state of Washington, where Semon's father worked as a civil engineer. In 1916, Semon enrolled in the University of Washington, where he first studied chemistry. Semon eventually changed his major to chemical engineering. Upon graduating in 1920, Semon enrolled in the University of Washington's graduate program, earning a doctoral degree in chemical engineering in 1924.
Semon remained as an instructor at the University of Washington until 1926. He earned approximately three thousand dollars each year in this position, and he supplemented his income by performing consulting work. In 1926, the Washington government implemented a law that required all government employees to turn over their consulting fees to the state government. Rather than remain in Washington, Semon accepted a position at the B.F. Goodrich Company in Akron, Ohio.
Upon arriving at B.F. Goodrich, Semon's first task was to find a way to bond rubber with metal. After trying numerous other substances, Semon tested polyvinyl chloride, which is also known by the acronym PVC. After adding various substances to PVC, Semon succeeded in creating a flexible, water-proof, and fire-resistant plastic that could bond to metal as well as be formed into products by itself.
Today PVC is the second most used plastic in the world, with manufacturers producing nearly forty-four billion pounds per year. Retail sale of PVC earns producers a combined twenty billion dollars per year. More than fifty percent of PVC manufactured today is used in construction materials, especially pipes and window frames. Other uses for PVC include credit cards and vinyl records.
Semon's next major breakthrough at B.F. Goodrich came in 1940, when he developed a new means of manufacturing synthetic rubber. Semon developed a new and cheaper version of synthetic rubber known as Ameripol. Ameripol made synthetic rubber production much more cost effective, helping Akron rubber companies, including B.F. Goodrich, Goodyear Tire and Rubber Company, and Firestone Tire and Rubber Company, to meet the country's needs during World War II (1941-1945). Semon's invention helped end the United States' dependence on foreign rubber. Upon World War II's conclusion, these same companies began to produce synthetic rubber items for peacetime use as well.
Over the course of his life, Semon received 116 patents for his inventions. While PVC and Ameripol were probably his two most important inventions, Semon was proudest of having developed synthetic-rubber bubble gum. Made from synthetic rubber, this bubble gum was still chewable. It also allowed someone to blow significantly larger bubbles than they could with normal chewing gum.
Upon retiring from B.F. Goodrich in 1963, Semon became a research professor at Kent State University in Kent, Ohio. He died on May 26, 1999, in Hudson, Ohio.