Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
Guilio Natta (1903-1979) and Karl Ziegler (1898-1973) shared the 1963 Nobel prize in chemistry and now this Swedish stamp for their work in polymer and organometallic chemistry. Ziegler was able to polymerize ethylene under ambient conditions with trialkyl aluminum and titanium chloride as catalysts, which had important applications for the plastics industry. Natta went one step further from Ziegler's research to achieve the stereo-regular polymerization of propylene, butene-1, and styrene. Stereo-regular polymers had been found in nature, but as yet not produced in the laboratory. Such a chain, regular in the stereochemical configurations of its repeat units, is shown on the stamp beneath the spider's web, whose silk is itself a polyalanine, with a certain amount of randomness and not simple repeats in its structure.