The present invention relates to a method for olefin oligomerization and comprising i) injecting an olefin monomer and a solvent into a continuous stirred tank reactor (CSTR); ii) injecting an oligomerization catalyst system comprising a ligand compound, a transition metal compound, and a co-catalyst into the continuous stirred tank reactor; and iii) performing a multimerization reaction of the olefin monomer, wherein a ratio of the flowing rates of the olefin monomer and the solvent is from 1:1 to 2:1. In the method for olefin oligomerization according to the present invention, high linear alpha-olefin selectivity may be attained even with a small amount of a solvent used by controlling reaction conditions during the multimerization reaction of olefin by a continuous reaction using a continuous stirred tank reactor.

A bimodal polymer composition comprising a lower molecular weight homopolymer and a higher molecular weight copolymer wherein the bimodal polymer composition has a density of from about 0.930 gram per cubic centimeter (g/cc) to about 0.970 g/cc, a ratio of high load melt index:melt index of from about 10 to about 150 and an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561. A chromium-catalyzed polymer composition comprising (i) a lower molecular weight homopolymer and (ii) a higher molecular weight copolymer, wherein the bimodal polymer composition has an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561.

A bimodal polymer composition comprising a lower molecular weight homopolymer and a higher molecular weight copolymer wherein the bimodal polymer composition has a density of from about 0.930 gram per cubic centimeter (g/cc) to about 0.970 g/cc, a ratio of high load melt index:melt index of from about 10 to about 150 and an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561. A chromium-catalyzed polymer composition comprising (i) a lower molecular weight homopolymer and (ii) a higher molecular weight copolymer, wherein the bimodal polymer composition has an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561.

The invention relates to tungsten oxo alkylidene complexes ligated with a tetraphenylphenoxy ligand and a neutral ligand such as a phosphine or a pyridine, and method of making the complexes. The complexes are useful as catalysts for performing a ring-opening metathesis polymerization of dicyclopentadiene to poly(dicyclopentadiene).

Processes for producing an activated chromium catalyst are disclosed, and these processes comprise contacting a supported chromium catalyst with a gas stream containing from 25-60 vol % oxygen at a peak activation temperature of 550-900° C. to produce the activated chromium catalyst. The linear velocity of the gas stream is 0.18-0.4 ft/sec, and the oxygen linear velocity of the gas stream is 0.05-0.15 ft/sec. The resultant activated chromium catalyst and an optional co-catalyst can be contacted with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.

The present invention concerns a process for the preparation of a copolymer comprising the steps of copolymerizing under suitable reaction conditions at least one first type of olefin monomer and at least one second type of functionalized olefin monomer using a catalyst system to obtain a polyolefin main chain having one or multiple functionalized short chain branches, the catalyst system comprising: i) a single-site catalyst or catalyst precursor comprising a metal selected from Ti3+ or Cr3+; ii) a co-catalyst; iii) optionally a scavenger.

The present invention concerns a process for the preparation of a copolymer comprising the steps of copolymerizing under suitable reaction conditions at least one first type of olefin monomer and at least one second type of functionalized olefin monomer using a catalyst system to obtain a polyolefin main chain having one or multiple functionalized short chain branches, the catalyst system comprising: i) a single-site catalyst or catalyst precursor comprising a metal selected from Ti3+ or Cr3+; ii) a co-catalyst; iii) optionally a scavenger.

Processes for producing an activated chromium catalyst are disclosed, and these processes comprise contacting a supported chromium catalyst with a gas stream containing from 25-60 vol % oxygen at a peak activation temperature of 550-900° C. to produce the activated chromium catalyst. The linear velocity of the gas stream is 0.18-0.4 ft/sec, and the oxygen linear velocity of the gas stream is 0.05-0.15 ft/sec. The resultant activated chromium catalyst and an optional co-catalyst can be contacted with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.

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.

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.