Propylene was first polymerized to a crystalline isotactic polymer by
Giulio Natta as well as by the German chemist Karl Rehn in March 1954.
This pioneering discovery led to large-scale commercial production of isotactic polypropylene by the Italian firm Montecatini from 1957 onwards.
Syndiotactic polypropylene was also first synthesized by Natta and his coworkers.
Polypropylene is the second most important plastic with revenues expected to exceed US$145 billion by 2019.
The demand for this material was growing at a rate of 4.4% per year between 2004 and 2012.
An important concept in understanding the link between the structure of polypropylene and its properties istacticity. The relative orientation of each methyl group relative to the methyl groups in neighboring monomer units has a strong effect on the polymer's ability to form crystals.
A Ziegler-Natta catalyst is able to restrict linking of monomer molecules to a specific regular orientation,either isotactic,when all methyl groups are positioned at the same side with respect to the backbone of the polymer chain,or syndiotactic,when the positions of the methyl groups alternate.
Commercially available isotactic polypropylene is made with two types of Ziegler-Natta catalysts. The first group of the catalysts encompases solid (mostly supported) catalysts and certain types of soluble metallocene catalysts.
Such isotactic macromolecules coil into a helical shape; these helices then line up next to one another to form the crystals that give commercial isotactic polypropylene many of its desirable properties.
This pioneering discovery led to large-scale commercial production of isotactic polypropylene by the Italian firm Montecatini from 1957 onwards.
Syndiotactic polypropylene was also first synthesized by Natta and his coworkers.
Polypropylene is the second most important plastic with revenues expected to exceed US$145 billion by 2019.
The demand for this material was growing at a rate of 4.4% per year between 2004 and 2012.
An important concept in understanding the link between the structure of polypropylene and its properties istacticity. The relative orientation of each methyl group relative to the methyl groups in neighboring monomer units has a strong effect on the polymer's ability to form crystals.
A Ziegler-Natta catalyst is able to restrict linking of monomer molecules to a specific regular orientation,either isotactic,when all methyl groups are positioned at the same side with respect to the backbone of the polymer chain,or syndiotactic,when the positions of the methyl groups alternate.
Commercially available isotactic polypropylene is made with two types of Ziegler-Natta catalysts. The first group of the catalysts encompases solid (mostly supported) catalysts and certain types of soluble metallocene catalysts.
Such isotactic macromolecules coil into a helical shape; these helices then line up next to one another to form the crystals that give commercial isotactic polypropylene many of its desirable properties.
