ABSTRACT
The year 1954 was a major breakthrough for the plastics industry; there was the invention of the stereospecific catalysts by Carl Ziegler and Guillo Natta. The Ziegler-Natta catalysts, initially commercialized by the Phillips Petroleum Company (now Chevron-Phillips Corp.), made it possible to produce linear high-density polyethylene (HDPE) via the use of lower pressures than those required for the Imperial Chemical Incorporated-low density polyethylene (ICI-LDPE) process (30,000-40,000 psi). Another milestone occurred in the plastics industry in the early 1990s; Exxon Chemical Company (now Exxon-Mobil Corp.) and Dow Plastics in 1991 and 1993, respectively, commercialized the use of metallocene catalysts. They have since been joined by Chevron-Phillips Corp. Metallocene catalysts, originally invented by Professor Walter Kaminsky of the University of Hamburg, Germany, are based on the extraordinary activating efficiency of methylaluminoxane (MAO) with biscyclopentadienyl metal compounds. Metallocenes have revolutionalized the polyethylene industry, especially in the film and packaging areas. Metallocene catalysts-based polyolefin films have enhanced clarity, toughness, strength, and barrier properties.
