You really have to do something major to have a street named after you. You can thrill the world with music, you can make an impact in politics, you can become a star athlete, or like Daniel Fox, you can invent a plastic. Dan Fox Drive in Pittsfield Massachusetts is a tribute to the man who gave the world polycarbonate, a plastic that was to profoundly alter our lives.
Dr. Fox graduated with a PhD from the University of Oklahoma in 1952 and soon found a job as a research chemist with General Electric in Schenectady, N.Y. At the time G.E. researchers were looking for novel materials to be used as insulation for electric wires but were repeatedly stymied. Every material they tried deteriorated when exposed to water. It was at this point that Fox remembered a curious substance he had encountered in graduate school.
Fox had been working with guiacol, a compound that was found in creosote, the black oily guck that builds up inside chimney flues as a result of incomplete burning of wood or coal. There was interest in guiacol because of its potential to be converted into compounds that had applications in the pharmaceutical and food industries. Guiacol itself had antiseptic properties and also served as a potential raw material for the synthesis of vanillin, the major flavour component of the vanilla bean. As part of his research, Dr. Fox synthesized a number of guiacol derivatives, one of which was guiacol carbonate. Interestingly, this compound resisted breakdown, even in boiling water. At the time this didn’t seem to have any great importance, but now at G.E. Fox was searching for just such a material.
Guiacol carbonate was water resistant all right, but it was a simple molecule that could not be formulated into any sort of a plastic. But Fox understood how carbonates were synthesized and realized that if he started with the right ones he could link them together into long chains, in other words, into “polycarbonates.” There was a good chance that such a polymer would have the properties he desired. Alas, when he mixed his chemicals, all he got was a glob of a material that was so hard he couldn’t even remove his stirring rod. This was certainly not going to be any sort of insulating material. But it was interesting enough to keep around the lab. The blob of glob became a curiosity, sometimes used to drive nails, sometimes thrown down stairs in futile attempts to shatter it. No luck with that.
Hmmm, Fox thought, a plastic that doesn’t break ought to be patented! And in 1955, just two years after he had come across the novel material, Dr. Fox applied for a patent. As is routine with any new patent application, he carried out a patent search and discovered much to his amazement that the German chemical company Bayer had applied for a polycarbonate patent the same year! Apparently Dr. Hermann Schnell at Bayer had independently come up with a plastic almost identical to Fox’s. Since neither patent had yet been granted, the two companies held discussions and forged a working agreement. Whichever company was granted legal priority, it would allow the other one to manufacture polycarbonate as long as appropriate royalties were paid.
As it turned out, this worked in G.E’s favour. The patent was awarded to Bayer since the company was able to document that Schnell had invented polycarbonate a week before Fox gave birth to his discovery. Polycarbonate, it seems, had two legitimate fathers! It wasn’t long before G.E found a use for the new plastic. At the time, the company had a monstrous problem with electrical meter covers then made of glass. Rambunctious teenagers, stones, and glass meter covers were not a good mix, as G.E. found out. But meter covers made of polycarbonate could readily withstand the teenagers’ assaults! Lexan, as General Electric named its polycarbonate, was off and flying. Before long, it was really flying. Into outer space!
Astronauts helmets had to be able to withstand impact at both high and low temperatures, and the visors had to have exceptional clarity. Polycarbonate fit the bill. That “one small step for man, one giant leap for mankind” could not have been taken without polycarbonate. The plastic also leaped into car headlight assemblies, safety glasses, bullet resistant shields, fighter plane canopies, skylights, and “unbreakable” bottles. A polycarbonate tunnel allowed visitors at SeaWorld to walk through a shark tank. Many viewed the predators through lightweight, shatterproof plastic eyeglasses made of polycarbonate.
Then along came the electronic age, essentially made possible by polycarbonate. Computer casings, cell phones, and perhaps most importantly, compact discs and DVDs are all made of this remarkable plastic. It’s the only one that meets the strength, weight and optical purity characteristics needed for compact audio and video discs. Our life would truly be different without this plastic. In more ways than one.
The raw material needed to make polycarbonate is bisphenol A (BPA)! The very same compound that has made headlines because of its potential toxicity. Traces of BPA show up in our blood and urine, which is no surprise given that it is impossible to keep a chemical that is produced in such massive amounts from escaping into the environment to some small extent. But most of our BPA exposure actually comes from food, basically through the leaching of trace amounts from the epoxy resin that lines the inside of food cans. Like polycarbonate, it is formulated with bisphenol A.
The canning industry is frantically searching for a replacement, even though any effect of BPA on humans is controversial, to say the least. Contrary to some claims, BPA does not build up in the body, the amount we take in is equal to the amount we eliminate in the urine. Still, replacing the epoxy resin in can linings is a reasonable application of the precautionary principle. But clamoring for the total elimination of BPA is unrealistic, unscientific and unnecessary. Unless, that is, we’re ready to forget about our hockey and bicycle helmets, laptops, CDs, DVDs and cell phones.