This historical landmark jointly honours two places, where pioneering discoveries were made by the German group headed by Karl Ziegler and the Italian group headed by Guilio Natta. These scientists are closely associated with each other and their groups were tightly bonded. Initially they were linked by their cooperative and competitive research and development activities. Then they shared the Nobel Prize for Chemistry in 1963 and until today “Ziegler–Natta” is a well known term within the Chemistry community. It is applied e.g. to olefin polymerization using organometallic catalysts. It should be noted that the Science History Institute honours the two scientists in a shared historical biography.
The landmark focuses on the two sites where the chemistry of Ziegler and Natta was born: one in Mülheim and the other in Milano. The historic laboratory building of the Max-Planck-Institut (MPI) für Kohlenforschung in Mülheim, built in 1914, listed as a historic monument where Karl Ziegler’s team made its groundbreaking discoveries will be the seat in Germany. Since 2008, it has been designated a Historical Site of Chemistry by the German Chemical Society. The “Giulio Natta” Department of Chemistry, Materials and Chemical Engineering at the Politecnico in Milano, will be the seat in Italy. In the historical building located at the Leonardo da Vinci square, there are many places and items that testify the activity and cultivate the legacy of Giulio.
The historical role of the scientific and technological achievements of both European groups as well as their impact on our everyday life are immense and is fully acknowledged at the European level and worldwide. Synthetic polymers had already existed since the end of the 19th century. Their material properties were partly unsatisfactory, their production often very expensive and only possible under high pressures. Zieglers research team discovered in 1953 that organometallic compounds could catalyse the production of polyethylene without the need for high pressure and temperature, leading to high-density polyethylene. This type of polyethylene proved superior to the previously manufactured products due to its better properties and more economical production, which made it possible to replace materials that were harmful to the environment in their production. It is still of utmost economic importance today. In 1953 Natta extended the research conducted by Ziegler to the stereospecific polymerization, thus discovering new classes of polymers with a sterically ordered structure. These studies led to the production of a thermoplastic material, isotactic polypropylene, which was soon marketed successfully as a plastic material for fibers and films. Important is his subsequent research which led to the synthesis of completely new rubbers, in two different ways: by polymerization of butadiene into cis-1,4 polymers and by copolymerization of ethylene with other olefins.
The impact of the scientific and technological achievements in the field of polymer science in the two sites has been outstanding. The discovered polyolefins are presently the mostly used plastics while the discovered unsaturated and saturated elastomers represent a large part of the present market of industrial rubbers. However, the materials obtained by Ziegler-Natta polymerizations were so successful that mankind, which had immediately recognized their countless useful applications and still strongly relies on their use, is nowadays also facing problems associated with the life cycle of polymers and their uncontrolled disposal. The two historical landmarks could be a perfect opportunity to show to the general public environmental sustainability of polymers as well as to underline modern contributions of Chemistry to Circular Economy.