|Born||September 10, 1898
|Died||May 26, 1999 (aged 100)|
|Alma mater||University of Washington (B.S., Ph.D.)|
|Awards||Charles Goodyear Medal (1944)
Elliott Cresson Medal (1964)
He was born on September 10, 1898.
Semon is best known for inventing vinyl, the world's second most used plastic. He found the formula for vinyl by mixing a few synthetic polymers, and the result was a substance that was elastic, but wasn't adhesive. Semon worked on methods of improving rubber, and eventually developed a synthetic substitute. On December 11, 1935, he created Koroseal from salt, coke and limestone, a polymer that could be made in any consistency. Semon made more than 5,000 other synthetic rubber compounds, achieving success with Ameripol (AMERican POLymer) in 1940 for the B.F. Goodrich company. In all, Semon held 116 patents, and was inducted into the Invention Hall of Fame in 1995 at age 97.
Semon is sometimes credited with inventing bubble gum, but this is inaccurate. He did invent an indigestible synthetic rubber substance that could be used as a bubble gum (and produced exceptionally large bubbles), but the product remained a curiosity and was never sold. Semon graduated from the University of Washington earning a BS in chemistry and a PhD in chemical engineering.
He was awarded the Charles Goodyear Medal in 1944 and the Elliott Cresson Medal in 1964. After retiring from B.F. Goodrich, he served as a research professor at Kent State University in Kent, Ohio.  He died in Hudson, Ohio, on May 26, 1999.
Waldo Semon Woods Conservation Area, is named in honor of the inventor, for his donation of land to Metro Parks, serving Summit County, Ohio. It is over 100 acres, with a pond where herons, turtles and amphibians are often seen.
- "WALDO SEMON (1898-1999)". Inventor of the Week. Michigan Institute of Technology. November 1999. Retrieved 2007-12-13.
- Elizabeth M. Smith, ed. (1993). A man of ideas : the biography of Dr. Waldo Lonsbury Semon, inventor of plasticized polyvinyl chloride. Cleveland: the Geon Company.
- Current Biography 1940, pp 723-24
- Current Biography 1940, p. 724