The successful application of olefin gas-phase polymerization processes shows the progress of polymerization processes and reactor design. Detection and control of the atmosphere composition in the gas phase is of great importance to design of gas-phase polymerization reactor, especially for copolymerization reactor, because the atmosphere composition in the gas phase has an important influence on the polymerization kinetics and the properties of the polymers obtained. In this work, a method for controlling the atmosphere composition during gas-phase copolymerization of ethylene, propene and hydrogen was developed. Ethylene/propene gas-phase copolymerization with little hydrogen during synthesis of PP/P(E-co-P) in-reactor alloy was carried out, and the atmosphere composition was controlled at an almost constant level. The effect of the atmosphere composition in the reactor on gas-phase polymerization was investigated and the reactivity ratios of ethylene and propene were estimated.

Keywords: olefin copolymerization, gas-phase polymerization, atmosphere composition control, reactivity ratios.