September 10 – Today In Science History – Waldo Semon


Waldo Semon

Waldo Semon – Discovered plasticized PVC or vinyl. Credit: Washington University Chemical Engineering Department

September 10 is Waldo Semon’s birthday. Semon was the American chemical engineer that invented one of the most used plastics in the world, vinyl.

Vinyl is the plasticized form of poly vinyl chloride or PVC. PVC was originally discovered by German chemist August Wilhelm von Hoffman in 1872. He found the material hard, brittle and little more than a curiosity. It was rediscovered by another German chemist, Friedrich Heinrich August Klatte. Klatte found the same properties as von Hoffman and set his container of PVC off to the side for future study. Over the course of time, sunlight polymerized Klatte’s sample to the rigid, but less brittle form we know today. Klatte obtained a patent in Germany but did not pursue any commercial use of the material.

Semon was working as a chemical engineer for the B.F. Goodrich company in 1926. He was attempting to find an adhesive polymer that would help bond rubber to metal. He was attempting to treat PVC to obtain a different polymer by removing the chlorine using solvents. Instead of producing an adhesive, he found a flexible version of PVC. Goodrich began marketing the product under the name Koroseal. Koroseal was used to waterproof cloth, coat electrical wiring and as seals for shock-absorbers. Another company, Union Carbide would use this plastic mixed with vinyl acetate to the music industry in the form of vinyl records.

Today PVC is the third most used plastic after polyethylene and polypropylene. You will encounter some form of plasticized PVC nearly everywhere. It is on the sides of houses, garden hoses, auto parts, and most commonly in plumbing. It is estimated that in the US alone, PVC tubing accounts for up to 75% of plumbing.

If that wasn’t enough, Semon also invented a synthetic rubber known as Ameripol and contributed greatly to the development of styrene rubber substitutes during World War II. One of his favorite inventions was a type of synthetic bubble gum. It looked just like gum but allowed the chewer to blow really large bubbles. B.F. Goodrich did not believe anyone would chew fake gum you could blow bubbles with and did not market Semon’s idea. Bubblegum would be invented again by the Fleer Chewing Gum company’s accountant in 1928.

Notable Science Events for September 10

1983 – Felix Bloch died.

Felix Bloch (1905 - 1983)

Felix Bloch (1905 – 1983)

Bloch was a Swiss physicist who shares the 1952 Nobel Prize in Physics with Edward Mills Purcell for their independent discovery of nuclear magnetic resonance (NMR). Bloch discovered NMR while investigating the magnetic properties of atomic nuclei.

Bloch also served as the first director of the European high-energy laboratory, CERN.

1975 – George Paget Thomson died.

George Paget Thomson

George Paget Thomson (1892 – 1975)
Nobel Foundation

Thomson was an English physicist who shares the 1937 Nobel Prize in Physics with Clinton Davisson for demonstrating the wave properties of an electron. Both men made the same discovery independent of each other. Thomson found that electrons could be diffracted just like waves and supplied the first proof of de Broglie’s hypothesis of wave-particle duality.

George Thompson was the son of J. J. Thomson, the discoverer of the electron.

1898 – Waldo Semon was born.

1892 – Arthur Holly Compton was born.

Arthur Compton

Arthur Compton (1892 – 1962)

Compton was an American physicist who was awarded half the 1927 Nobel Prize in Physics for his discovery of the Compton effect.

The Compton effect occurs when x-rays interact with matter and transfers part of that energy to a single electron. This energy transfer excites the electron to a higher energy state. When the electron returns to its ground state, a photon is created and transmitted in a definite direction based on the incident energy’s direction.

1797 – Carl Gustaf Mosander was born.

Carl Gustaf Mosander (1797 - 1858)

Carl Gustaf Mosander (1797 – 1858)

Mosander was a Swedish chemist who discovered the first lanthanides. He was investigating rare earth minerals and discovered the elements lanthanum, terbium, and erbium. He also believed he discovered another element he named didymium.

Didymium was later determined to not be an element but a mixture of the elements praseodymium and neodymium.

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