摘要:
Ethylene polymerization processes and polymers formed from the same are discussed herein. The ethylene polymerization processes generally include introducing ethylene monomer into a polymerization reaction zone; introducing a chromium oxide based catalyst into the polymerization reaction zone; introducing a quantity of hydrogen into the polymerization reaction zone; and contacting the ethylene monomer with the chromium oxide based catalyst in the polymerization reaction zone in the presence of hydrogen to form polyethylene, wherein the polyethylene formed in the presence of hydrogen exhibits an MI2 that increases with an increasing quantity of hydrogen and a molecular weight and molecular weight distribution that remains essentially constant with an increasing quantity of hydrogen.
摘要:
A method comprising preparing a reaction mixture comprising a styrene monomer, an antioxidant, and a reaction rate improving additive, contacting the reaction mixture with an antioxidant reactive compound, and placing the reaction mixture under conditions suitable for polymerization of the styrene monomer to a styrenic polymer wherein the polymerization occurs at an overall reaction rate that is increased by equal to or less than 20% when compared to an otherwise similar polymerization process carried out in the absence of the reaction rate improving additive A method comprising preparing a reaction mixture comprising a styrene monomer, an elastomer, an antioxidant, a sodium or calcium salt of an organic acid, and an initiator; and placing the reaction mixture under conditions suitable for polymerization of the styrene monomer to a styrenic polymer, wherein the sodium or calcium salt of an organic acid protects the initiator such that the polymerization is carried out at a reaction rate greater than would otherwise be the rate in the absence of the sodium or calcium salt of an organic acid.
摘要:
Methods of forming polyolefins and catalysts are described herein. Such methods generally include forming Ziegler-Natta catalyst compounds in the absence of one or more blended compounds typically used to form such catalyst.
摘要:
A method of preparing a reaction mixture comprising a styrene monomer, an antioxidant, and a reaction rate improving additive, contacting the reaction mixture with an antioxidant reactive compound, and placing the reaction mixture under conditions suitable for polymerization of the styrene monomer to a styrenic polymer wherein the polymerization occurs at an overall reaction rate that is increased by equal to or less than 20% when compared to an otherwise similar polymerization process carried out in the absence of the reaction rate improving additive. The reaction rate improving additive can be a sodium or calcium salt of an organic acid.
摘要:
Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW·h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW·h/ton, and forming an article.
摘要:
Ziegler-Natta catalysts, processes of forming the same and using the same are described herein. The process generally includes contacting a metal component with a magnesium dihalide support material to form a Ziegler-Natta catalyst precursor; contacting the support material with a dopant including a non-Group IV metal halide to form a doped catalyst precursor; and activating the doped catalyst precursor by contact with an organoaluminum compound to form a Ziegler-Natta catalyst.
摘要:
The present invention relates generally to catalysts, to methods of making catalysts, to methods of using catalysts, to methods of polymerizing, and to polymers made with such catalysts. More particularly, the present invention relates to polyolefin catalysts and to Ziegler-Natta catalysts, to methods of making such catalysts, to methods of using such catalysts, to polyolefin polymerization, and to polyolefins.
摘要:
Polyolefins may be prepared using a cocatalyst conforming to the formula: AIRz(Xz)nLzm wherein Rz is a linear or branched organic moiety having at least 5 carbons and Xz is a linear or branched organic moiety having at least 5 carbons or a heterocyclic moiety having at least 4 atoms and can be anionic or di-anionic. The aluminum complex may also be in the form of an adduct complex where Lz is a Lewis base and m=1-3. The cocatalyst Rz components are selected such that they do not react with water under polymerization conditions to form a species that is highly soluble in the polymerization diluent. Use of the specified cocatalyst reduces fouling during metallocene-catalyzed runs and “post-metallocene hangover” when the same production equipment is transitioned to non-metallocene catalyst runs using catalysts such as chromium.
摘要:
Catalyst systems, processes of forming the same and polymers formed therefrom are described herein. The processes of forming the catalyst systems generally include contacting a blend of an alkyl magnesium compound and an organoaluminum compound with an alcohol to form a magnesium dialkoxide compound; contacting the magnesium dialkoxide compound with a first agent to form a solution of reaction product “A”, the first agent including a halogenating/titanating agent; contacting the solution of reaction product “A” with a second agent to form a solid reaction product “B”, the second agent including a blend of a first metal halide and a metal alkoxide; contacting the solid reaction product “B” with a third agent to form a solid reaction product “C”, the third agent including a second metal halide; contacting the solid reaction product “C” with a fourth agent to form a solid reaction product “D”, the fourth agent including a third metal halide; contacting the solid reaction product “D” with a fifth agent to form a catalyst component, the fifth agent including a reducing agent; and heating an intermediate selected from reaction product “A”, reaction product “B”, reaction product “C”, reaction product “D” and combinations thereof to form a heat-treated catalyst that results in a shear response and a molecular weight distribution for a polymer produced by the heat-treated catalyst that are greater than a shear response and a molecular weight distribution for a polymer produced by an identical non-heat-treated catalyst.
摘要:
A method of making a styrenic composition having a high melt strength including combining a styrenic monomer and a second monomer to form a combined mixture and subjecting the combined mixture to polymerization to obtain a styrenic co-polymer, wherein the second monomer comprises a hydroxyl functional group and wherein the styrenic composition has a greater melt strength than that of general purpose polystyrene.