The Nobel Prize in Chemistry 1963 was awarded jointly to Karl Ziegler and Giulio Natta "for their discoveries in the field of the chemistry and technology of high polymers".
 

Plastics consist of very large molecules or macromolecules often forming long chains of thousands of atoms. Acting upon his fortuitous observation, Ziegler systematically tested a range of related compounds, until he arrived at a combination that could link together the small chemical monomer ethylene to form polyethylene chains that were longer and had fewer branches, and crucially could achieve this under less intense temperatures and pressures than the methods used at the time. However, Professor Natta has found that certain types of Ziegler catalysts lead to stereoregular macromolecules, i.e. macromolecules with a spatially uniform structure. The secret is that the molecular environment of the metal atom, at which new units are stuck on to the chain as mentioned before, is so shaped that it permits only a definite orientation of the side groups.