METHOD FOR CONTROLLING POLYOLEFIN PROPERTIES DURING POLYMERISATION

摘要

Disclosed herein are methods of controlling polymer properties in polymerization processes that use a chromium-based catalyst. An embodiment discloses a method of producing a polyolefin comprising: contacting a reaction mixture and a reduced chromium oxide catalyst in a gas-phase reactor to produce the polyolefin, wherein the reaction mixture comprises a monomer and a co-monomer; and changing a reaction temperature in the gas- phase reactor by about 1o C or more whereby a gas molar ratio of the co-monomer to the monomer is changed by about 2 pcnt or more and a co-monomer content of the polyolefin at substantially constant density is changed by about 2 pcnt or more. Additional methods and compositions are also provided.