Alongside the theoretical and practical studies on polymers the essential chemical mechanism of polymerization and copolymerization was clarified, this work culminated in 1954 with K.Ziegler and G.Natta’s findings on the catalyzers of ethylene polymerization.
Natta and his collaborators at the Polytechnic of Milan and of Montecatini obtained a class on highly crystalline polymers with these catalyzers which were called isotactic, because they were made up of long sequences of monomeric units with the same configuration. One of these was Moplen, industrially produced in 1957 by Montedison at Ferrara.
Polypropylene turned out to be a very important polymer on an industrial level and its production increased rapidly all over the world, particularly in the United States, (in spite of litigations regarding the priority of the invention), Japan, Great Britain and, naturally, in Italy.
In 1962 world production of this polymer had reached 300,000 tons. Today the total amount produced is 15 million tons and the growth rate is the highest among all the more widely consumed thermoplastics.
In the meantime a new plastic had been developed during those years: polyvinyl chloride resin. The vinylic resin story is witness to the tenacity of research workers. It was E.Bauman in 1872 who studied the polymerization process of vinyl chloride and revealed the importance of the thermoplastic product which could be obtained.
However, industrial production of vinylic polymers had to wait for the work of F.Hatte and Ivan Ivanovic Ostromislenski (1880-1939). In 1927 the American Union of Carbide Chemicals produced the first copolymers of vinyl chloride-acetate which were made on an industrial scale only from 1939.
