Univation Technologies, LLC

Francois Alexandre

Mark Gregory Goode

William Albert Matthews

Kevin Joseph Cann

John H Moorhouse

Timothy R Lynn

Cliff Robert Mure

Kefu Sun

Barbara J Kopp

Charles D Lester

Samuel Bernal

Ayush A Bafna

Ping P Cai

Bo Liu

John H Moorehouse

Yi Zhang

Robert N Reib

William A Matthews

Embodiments of the present disclosure are directed towards method for modifying a polymer flow index. As an example, a method for modifying a polymer flow index can include providing monomers to a polymerization reactor, providing a chromium catalyst to the polymerization reactor, and providing an active amount of a flow index modifier to the polymerization reactor, wherein the flow index modifier is selected from carbon dioxide, carbon monoxide, 2,4-hexadiene, and combinations thereof.

Polymer flow index modifier

The present disclosure provides for a system and method for producing a polyethylene polymer (PE) that includes measuring a melt flow index (MFI) of the PE, comparing the measured value of the MFI to a predetermined desired range for the MFI, changing a catalyst feed rate to the polymerization reactor based on the compared values of the MFI, where changes in the catalyst feed rate preemptively compensate for subsequent changes in an oxygen flow rate to the polymerization reactor that maintain a predetermined residence time and bring the MFI of the PE into the predetermined desired range for the MFI; and changing the oxygen flow rate to the polymerization reactor thereby maintaining both the predetermined residence time and bringing the MFI of the PE into the predetermined desired range for the MFI. The measuring and comparing steps are repeated to ensure the measured value of the MFI is within the predetermined desired range of the MFI at the predetermined residence time.

Producing a polyethylene polymer

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 1&#xb0; C. or more whereby a gas molar ratio of the co-monomer to the monomer is changed by about 2% or more and a co-monomer content of the polyolefin at substantially constant density is changed by about 2% or more. Additional methods and compositions are also provided.

Methods for controlling polymer properties

Embodiments of the present disclosure are directed towards methods for rating polymerization processes based upon a first cracking index value and a second cracking index value.

Rating polymerization processes

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Saint-Leonard, Canada

Francois Alexandre