Abstract:
A clay-filled polyolefin composition and process for making it are disclosed. The process involves treatment of a non-acid-treated smectite clay with a Ziegler-Natta catalyst in the presence of a hydrocarbon and subsequent polymerization of an olefin in the presence of the treated clay and an organoaluminum cocatalyst. Results indicate that filled compositions produced by this process contain exfoliated clay.
Abstract:
A polyethylene having improved rheological properties is disclosed. The polyethylene has a melt index (MI2) from about 0.01 dg/min to about 50 dg/min and a melt strength (&eegr;) that satisfies MI2×&eegr;≧3.5. A process for making the polyethylene is also disclosed. The process uses an azaborolinyl-containing single-site catalyst in the presence of hydrogen, where the hydrogen consumption is controlled to be less than 30%.
Abstract:
Supported heterometallocene catalysts wherein the support is a particulate polymeric material are provided. The catalysts have a transition metal complex containing at least one anionic, polymerization stable heteroatomic ligand associated with the transition metal and a boron activator compound deposited on the support. Polymeric supports used for the heterometallocene catalysts of the invention are homopolymers of ethylene and copolymers of ethylene and C3-8 &agr;-olefins.
Abstract:
A method of modifying a polyethylene is disclosed. In the method ethylene or a mixture of ethylene and a C3-C10 α-olefin is polymerized in an organic solvent with a Ziegler or single-site catalyst to form an initial polyethylene solution. The initial polyethylene solution is then reacted with a free radical initiator to produce a modified polyethylene. The modified polymer has an enhanced melt elasticity and increased long chain branching index, and is essentially free of gel.
Abstract:
A process for polymerizing olefins is disclosed. The process uses a hydrosilane in a polymerization catalyzed by an open architecture, bridged indenoindolyl organometallic complex and an activator. Polyolefins from the process have increased molecular weight.
Abstract:
A method for modifying a high-density polyethylene (HDPE)-clay nanocomposite is disclosed. The method comprises shearing a melt of the nanocomposite at an effective shear rate. The modified nanocomposite shows significantly increased complex melt viscosity, storage modulus, and loss modulus.
Abstract:
A method for producing propylene polymers having a broad molecular weight distribution (MWD) is disclosed. The method uses a Ziegler catalyst and one silane donor. The silane donor is selected from vinyltrimethoxysilane or dicyclohexyldimethoxysilane. The polymers made by the method have an MWD greater than or equal to 7.0.
Abstract:
An ethylene polymerization catalyst and catalyst system which provides an ethylene copolymer which is characterized by desirable ER shift values. The high level ER shift of these polymers produce films having high impact strength. The catalyst is prepared by treating a support material with an agent selected from the group consisting of a compound having the structural formula BX53, where X5 is fluorine, chlorine, bromine, iodine or OR5, where R5 is C1-C6 alkyl; a compound having the structural formula X62 where X6 is fluorine, bromine or iodine; a compound having the structural formula NR6, where R6 is C1-C6 alkyl or OR7, where R7 is C1-C8 alkyl; and a compound having the structural formula Ti(OR8)4, where R8 is C1-C6 alkyl or phenyl to reduced surface hydroxyl group concentration of the support material. The thus treated support material is thereupon contacted with a dialkylmagnesium compound or complex, an alcohol compound or a silane compound and a transition metal compound, in that order. Alternatively, the sequence of contact of the transition metal compound and the silane compound may be reversed, as may be the sequence of addition of the dialkylmagnesium compound or complex and the silane compound.
Abstract:
A method for preparing a titanium-containing Ziegler-Natta catalyst is disclosed. A dialkyl magnesium compound, a trialkyl aluminum compound, and a polymethylhydrosiloxane are first combined in a hydrocarbon solvent. That product is then combined with dry, alcohol-free magnesium chloride. A solid product from the reaction with the magnesium chloride component is isolated and washed with a hydrocarbon solvent. The washed solid product is then combined with an alkyl aluminum dichloride or a dialkyl aluminum chloride to give the catalyst. The catalyst is suitable for both slurry and gas-phase olefin polymerizations. Polyolefins produced with the catalyst have broad molecular weight distributions and narrow distributions of relatively large particles.
Abstract:
The invention relates to supports comprising inorganic oxide particles coated with magnesium chloride and a method for making them. The inorganic oxide has a mean particle diameter of less than 5 microns and is used as a seed to crystallize magnesium chloride from solution. The magnesium chloride-coated inorganic oxide is useful for supporting transition metal compounds; the supported transition metal compounds are used as catalysts for polymerizing olefins.