| Popis: |
Since the discovery of Ziegler-Natta catalysts and the first commercial exploitation and development of polypropylene, research has continued to understand and exploit the fundamental, molecular basis of this unique catalyst system. This understanding has expanded the potential of the polymerization process to allow development and production of olefinic polymers with unique combinations of properties never envisaged by its original discoverers. The initial titanium chloride/aluminum alkyl catalyst for the polymerization of propylene gave poor stereoregularity, resulting in a low percentage of the commercially viable isotactic polymer. The activities of the Natta Research School were directed towards a more stereospecific system and led to the first industrial process for the production of polypropylene in 1957. Although the stereoregularity of these polymers was sufficient, the efficiency of the TiCl3 catalysts was low (3000–5000 g. polymer/g. Ti) , and extracting of the polymer was required in order to remove catalyst residues and provide a practical, useful resin. |
