Giulio Natta and the origins of stereoregular polymers

Abstract

The name of Natta is entwined inextricably with that of Ziegler, in the famous catalyst systems known by their names and used to make polyethylene and polypropylene. Unlike ethylene, which is achiral, propylene is a prochiral molecule and upon polymerization can lead to interesting stereochemical and regiochemical enchainment sequences. Natta’s prescience in recognizing this unique feature of propylene led to the discovery of crystalline isotactic polypropylene and the beginning of a new industry. The story of how Natta discovered polypropylene is an engrossing one – one of stiff competition amongst contemporaries, Natta’s intimate relationship with the Italian industries, and his unique scientific background. Natta’s identification of isotactic polypropylene as a righthanded three fold ‘single helix’ in March 1954, in quick succession to the discovery of DNA ‘double helix’ by Watson, Crick, and Rosalind Franklin (March 1953), and the coiledcoil motif of ‘triple helix’ of collagen by G N Ramachandran (August 1954), makes this period the ‘golden age of macromolecular crystallography’.