GAS-PHASE ETHYLENE POLYMERIZATION - PRODUCTION PROCESSES, POLYMER PROPERTIES, AND REACTOR MODELING

A review of relevant macroscopic and microscopic processes of gas phase ethylene polymerization, both chemical and physical, is given. The commercial technology development of gas-phase ethylene polymerization processes is illustrated through a selective survey of the patent literature. Both advantages and disadvantages of gas phase polymerization processes are addressed, and the challenges of laboratory studies of gas phase polymerization are also outlined. Physicochemical phenomena of ethylene polymerization using heterogeneous catalysts are discussed, including examination of catalyst preparation, polymer morphological development, and elementary chemical reactions. Metallocene-based catalysts and their kinetic performance for olefin polymerizations are also discussed. The current state of the art for reactor modeling of polymerization rate, molecular weight development, reactor dynamics, and resin grade transition strategies is illustrated on the basis of the most recent academic studies. Finally, relationships between resin properties and polymer microstructures as well as characterization methods are described briefly. In particular, temperature-rising elution fractionation technology is emphasized for characterization of ethylene copolymers. The fundamental issues involved in gas phase ethylene polymerization and their interrelationships are also discussed in some detail.