It all started in 1838 when the French chemist Anselme Payen separated cellulose, the substance that makes up the cell walls of plants.
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Joe Schwarcz • Special to Montreal GazetteAsk how the ideas for these columns came about. May be about. In this case, it was looking at a discarded overhead projector. It reminded me of my first educational experience when all the lecture rooms were equipped with such equipment in 1973 and I wrote on a plastic sheet that we called "acetate". At the time, I wasn't thinking about the term, but an unwanted projector sitting in a trash can somehow made me think about all the chemistries I wrote on those acetates. .. And some of them were all about synthesizing the substance. "Acetic acid" refers to cellulose acetate, a material that has played an important role in war, photography, fashion, packaging and medicine.
It all started in 1838 when the French chemist Anselme Payen separated cellulose, the substance that makes up the cell walls of plants. Then, in 1865, another French chemist, Paul Schutzenberger, reacted cellulose with acetic anhydride to form a sticky substance, which he could not use. However, I was interested in the Swiss brothers Camille and Henri Dreyfus, who had PhDs from the University of Basel. In 1904, they began experimenting with cellulose acetate in their father's garden hut and discovered that it was soluble in acetone. When a thin layer of this solution was poured onto the surface, the acetone evaporated, leaving a sheet of plastic material. The idea was born immediately. Is this a celluloid replacement for photographic film cursed by flammability issues?
Now, we need a little history of celluloid. In 1832, Henri Braconault unknowingly synthesized nitrocellulose by combining wood fiber with nitric acid. This is a highly flammable substance that he named "xyloidin". German and Swiss chemists Christian Friedrich Schönbain discovered a more practical formulation of nitrocellulose in 1846 by treating cotton with a mixture of nitric acid and sulfuric acid. He was excited by Michael Faraday and wrote that he was able to shape this material into "everything and shape", but he didn't pursue it any further. Schonbein was more interested in "pyroxylin," which burns without smoke. This is an observation that leads to the production of smokeless powder.
Then, in 1856, Alexander Parkes of England added camphor to nitrocellulose to produce the world's first synthetic plastic, "Parquesin." Almost at the same time, John Wesley Hyatt in the United States came up with a very similar prescription inspired by his quest to win a $ 10,000 prize offered by a billiard ball company to develop an alternative to ivory. I did. It was Hyatt that coined the term celluloid for new plastics.
Celluloid has many uses, from interchangeable shirt collars and cuffs to combs and flexible photographic film introduced by George Eastman in the 1880s. .. However, all celluloid products had the same problem. They were very flammable. Cellulose acetate was not, so the Dreyfus brothers considered using it instead of celluloid in roll film. In 1912, they actually started producing acetate film, but then the fledgling airplane industry got in the way.
Early biplane wings were covered with canvas, which caused aviation problems when wet. A waterproof cover covered with a cellulose acetate lacquer called "dope" solved the problem. The UK Cellulose and Chemicals Manufacturer was founded by Camille Dreyfus to manufacture lacquers for aircraft wings, along with a similar business in the United States. It also proved to be an excellent coating of the fabric used in Zeppelin manufactured in Germany.
After the war, the Dreyfus brothers made another breakthrough. A solution of cellulose acetate was passed through a small hole in a device such as a shower head, resulting in fibers suitable for weaving into silky fabrics widely used in the fashion industry. To manufacture textiles, Camille Dreyfuss founded the American Cellulose&chemical manufacturing company in 1918 and purchased the celluloid company founded by John Wesley Hyatt and his brother Izaya in 1927. Dreyfus changed its name to the American Celanese Company under the name Celanese, which is derived from the cellulose acetate "cel" and the acetate fabric, which was derived from "ese" because it was so easy to care for. Even today, "acetate" appears on many labels and is often blended with silk, cotton, wool and nylon to create a smooth-feeling, wrinkle-resistant, quick-drying fabric. doing.
The Celanese Company was a huge success and the Drafus brothers became very wealthy. When Henri died in 1944, his brothers created a fund in his memory, and when Camille died in 1956, he was eventually renamed Camille and the Henrid Reifus Foundation. The Foundation manages a number of awards aimed at promoting chemistry research and education. Held every other year, the Dreyfus Prize recognizes those who have made significant advances in chemistry through outstanding and unique research, and awards a $ 250,000 award. The first award in 2009 was given to Professor George Whitesides of Harvard University, one of the most widely cited chemists in the world. He was recognized for creating new materials that have made significant strides in the field of chemistry and its social interests.
The Dreyfus brothers themselves would be worthy award candidates if they were still alive. Cellulose acetate has undoubtedly benefited society in many ways. Think about all the items that can be traced back to the early experiments by Camille and Henri Dreyfus. Magnetic tape, reverse osmosis filters, dialysis machine membranes, photographic "safety film", and, of course, a roll of acetate staring at me from its discarded overhead projector.
joe.schwarcz@mcgill.ca
Joe Schwarcz is the director of the& Society (mcgill.ca/oss), McGill University's Department of Science. is. He hosts the Dr. Joe Show on CJAD Radio 800AM every Sunday from 3pm to 4pm.
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