Mark M. Green (sciencefromaway.com)
In 1936, as tensions leading to the second world war were ratcheting up, a small company located in Philadelphia, Rohm and Haas, that had been started by a German chemist, learned that something new was afoot at the parent company in Germany, Rohm AG—some new kind of plastic, later to be called Plexiglas had been produced. A young chemist was sent to Germany to learn about the invention. Dr. Donald Frederick learned about this plastic but was not told that it had revolutionized air warfare. In the First World War, airplanes did not have the power to fly as high and as fast as the generation of planes preparing for the new war. We are used to the scenes of scarves streaming behind the pilots in their open cockpits with no problem breathing the oxygen rich air at these low altitudes. In this new war the pilots had to be shielded by closed cockpits and glass was a poor material for the job. Glass is heavy, burdening the engine and slowing the plane, and very important, glass shatters easily. A bullet or a piece of shrapnel however small could shatter the glass cockpit shielding the pilot. The German company had discovered that the new plastic was far lighter than glass, could be molded into many shapes and did not shatter if impacted or even penetrated. Although Dr. Frederick was shown the new plastic, the chemists at Rohm AG were not allowed to tell him about the revolutionary properties of this precursor to Plexiglas.
On returning to Philadelphia the Rohm and Haas chemists quickly prepared the precursor to the plastic, methyl methacrylate, and soon discovered the properties of the polymer, the plastic, derived from it. Rohm and Haas began selling the plastic in sheets. The first year sales in 1937 were only $13,000. By 1944 sales had reached 22 million dollars with Rohm and Haas’ contribution of a critical war material. In 1943 the United States produced 86,000 warplanes and they all used Plexiglas, the name given to the plastic by Rohm and Haas.
The term methyl in methyl methacrylate informs any chemist that there is an entity with only a single carbon atom (CH3) as part of the chemical structure. Chemists at Rohm and Haas wondered what would be the effect of using far larger entities instead of the methyl group. How about something as long as eighteen carbon atoms? Such long chains of carbon atoms are easily available since they occur in the fats found in all living organisms. There was an unexpected change in the properties of this new plastic, miscibility with motor oil. And this mixing caused the motor oil to remain fluid at very low temperatures. This was very interesting but without any apparent commercial value. A patent was filed without any expectation that the company would derive any financial benefit. At the beginning of the Second World War the United States government had a policy of searching through all the filed patents to see if anything might be useful. Attention focused on this patent, which had been thought to be useless, as of possible value in combat occurring with vehicles at very low temperatures, a situation that could occur in battles between the Germans and the Russians. Indeed, the Russians were told about these versions of Plexiglas with long carbon chains instead of the methyl group. They were added to the motor oil in the Russian tanks and when battles went on into the frigid cold of the Russian winter, the German tanks with their frozen motor oil were useless. In the tank battles in the siege of Stalingrad, a critical turning point in the war, this difference in motor oil fluidity played a critical role in defeat of the Nazi forces.
Next month we’ll hear another story about how a chemical discovery changed the outcome of the air war over England, a story connected to what goes on in petroleum refineries.