The Discovery of the Polypropylene

Written by  Luciano Luciani

Recalling the birth of the Montecatini Research Centre in Ferrara.

It was 1 March 1953 when I presented myself at then seat of the Montecatini centre in Milan, taken on as an apprentice by Professor Giulio Natta with a view to one day attending the Milan Polytechnic. Rather intimidated, I was greeted by the personnel officer and taken to meet Professor Natta who immediately introduced me to Professor Pino and Doctor Mazzanti so as to assign to me the research project I was supposed to undertake. As well as being nervous I was also rather bewildered at the speed with which everything had taken place. In June 1952 I had graduated in Chemistry from the University of Ferrara with a First Class Honours Degree with Distinction. A few months later, while I was still deciding what I wanted to do, I received an unexpected telegram from the Montecatini Centre inviting me to Milan for an interview with view to possible employment, The interview didn’t go very well, in that the committee of professors and directors expected knowledge beyond what I could offer. But nonetheless a short while later I received an invitation to take up a position. I had made an excellent impression on the committee: they had liked my character and my approach to tackling problems. I was assigned a position of great interest and importance: to attempt to construct long chain polymer molecules with the addition and concatenation of monomers (such as ethylene), a process neither understood nor possible at this time. Professor Natta had been very impressed by the results obtained by Professor Ziegler on the polymerisation of ethylene in the presence of aluminium triethyl. Consequently Natta suggested that the Montecatini centre should begin collaborative work with Ziegler to further pursue such experiments. To this end a research team was created in 1953 working both with Ziegler and with the Polytechnic of Milan, drawing on the very best new graduates from various universities. The team included names like P. Chini, M. Farina, E. Giochetti, R. Magri and others, including myself. I remember the great excitement of that pioneering period and my first preparation of the aluminium triethyl catalyst based on Ziegler’s research, as well as the experiments we carried out under high pressures with ethylene in the presence of aluminium triethyl. For months we worked incredibly hard. At the start of 1954,

Chini obtained a tiny quantity of a sticky substance which, after extraction and purification, gave a fraction of polymer, with a high molecular weight and a melting point of around 160°C. When I realised I was taking part in a great invention my emotions were indescribable. In Natta’s own diary on the date 11 March 1954 is written in his own hand: made polypropylene. His creative genius permitted us to progress in just a few months from synthesising “monomer propylene” to “polymeric isotactic propylene,” patenting the discovery and describing its chemical structure. At the start of the second term of 1954, with successful synthesis of polypropylene already underway, Natta invited me to Ferrara along with Magri to the Montecatini petrochemical factory (where during the war synthetic rubber had been produced) in order to further develop the research with other colleagues and technicians. From that moment the I.R.I. research centre in Ferrara was born, dedicated to the synthesis of polyolefins. In 1955 the Ferrara Research Centre was already a well organised and perfectly functioning structure. In fact, from the very beginning of the Centre’s activity, groups of researchers were established each with responsibility for developing separate areas of knowledge, such as catalysts and catalysis, polymerization and technology, the chemical, physical and mechanical characteristics of polymers, or product development and transformation with various processes and tests to explore possible commercial uses. Soon pilot equipment was being tested. The first large scale production of polypropylene was carried out in Ferrara at the end of the 1950s. Alongside this, with regard to applications, many different kinds of product were being developed including consumer goods, threads and fibres, film and oriented sheet, car parts, furnishings and home equipment and many other previously unimaginable possibilities. Today, after many years, the Giulio Natta Research Centre remains active and a world leader in research.