Linear high-density polyethylene discovery

Discovery of Linear (High-Density) Polyethylene Use of Comonomers Linear Low-Density Polyethylene Stereospecific Polymerization Discovery of Polypropylene Manufacturing Processes High-Pressure LDPE Low-Pressure, Linear HOPE LLDPE... 

In the 1950s, almost two decades after the launch of LDPE, transition metal catalysts proved capable of producing unbranched linear low density polyethylene (LLDPE) and linear high-density polyethylene (HOPE), both of which had significantly different properties from LDPE. Remarkably, the discovery occuued nearly simultaneously in three different research groups using three different catalyst systems. First was Standard of Indiana s reduced molybdate on alumina catalyst in 1951, followed by Phillips with chromium oxide on silica ( chromox ) catalysts, and Ziegler s titanium chloride/ alkylaluminum halide systems in 1953 (only the latter two were widely commercialized). At about the same time, crystalline polypropylene (PP) was produced in the Phillips labs... 

High-pressure polymerization of ethylene was introduced in the 1930s. The discovery of a new titanium catalyst hy Karl Ziegler in 1953 revolutionized the production of linear unhranched polyethylene at lower pressures. The two most widely used grades of polyethylene are low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Currently,... 

Commercial linear polyethylene, the most commonly used type of plastic, was bom more than half a century ago with the accidental discovery at Phillips Petroleum Company that chromium oxide supported on silica can polymerize a-olefins.1 The same catalyst system, modified and evolved, is used even today by dozens of companies throughout the world, and it accounts for a large share of the world s high-density polyethylene (HDPE) supply, as well as some low-density polymers. The catalyst is now more active and has been tailored in numerous ways for many specialized modem applications. This chapter provides a review of our understanding of the complex chemistry associated with this catalyst system, and it also provides examples of how the chemistry has been exploited commercially. It is written from an industrial perspective, drawing especially on the commercial experience and the research of numerous scientists working at Phillips Petroleum... 

From this brief survey of contemporaneous discoveries on polyolefin polymerization, it is evident that catalysis became a dominant technology factor to consider within 20 years of the discovery of high-pressure (low-density) polyethylene. These various catalysts enabled linear polyethylene of higher density and higher... 

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