A Ziegler-Natta catalyzed ethylene/alpha-olefins copolymer is provided having sporadic long chain branches and reversed comonomer composition distribution or short chain branching distribution (SCBD) in the high molecular weight fractions. According to the invention, polyethylene film made with the inventive copolymer has a balance of improved physical, optical, mechanical properties as well as processability. In one aspect, the film includes a 1% secant modulus of greater than 25,000 psi, a film haze of less than 10, a film clarity of greater than 90, a dart impart resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil.

A Ziegler-Natta catalyzed ethylene/alpha-olefins copolymer is provided having sporadic long chain branches and reversed comonomer composition distribution or short chain branching distribution (SCBD) in the high molecular weight fractions. According to the invention, polyethylene film made with the inventive copolymer has a balance of improved physical, optical, mechanical properties as well as processability. In one aspect, the film includes a 1% secant modulus of greater than 25,000 psi, a film haze of less than 10, a film clarity of greater than 90, a dart impart resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil.

Supported chromium catalysts containing a solid oxide and 0.1 to 15 wt. % chromium, in which the solid oxide or the supported chromium catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a loop slurry reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm.sup.3, from 150 to 680 ppm solid oxide (such as silica), from 1.5 to 6.8 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft.sup.2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm per five grams of the ethylene polymer.

Supported chromium catalysts containing a solid oxide and 0.1 to 15 wt. % chromium, in which the solid oxide or the supported chromium catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a loop slurry reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm.sup.3, from 150 to 680 ppm solid oxide (such as silica), from 1.5 to 6.8 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft.sup.2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm per five grams of the ethylene polymer.

A method of preparing a catalyst comprising a) contacting a non-aqueous solvent, a carboxylic acid, and a chromium-containing compound to form an acidic mixture; b) contacting a titanium-containing compound with the acidic mixture to form a titanium treatment solution; c) contacting a pre-formed silica-support comprising from about 0.1 wt. % to about 20 wt. % water with the titanium treatment solution to form a pre-catalyst; and d) thermally treating the pre-catalyst to form the catalyst. A method of preparing a catalyst comprising a) contacting a non-aqueous solvent and a carboxylic acid to form an acidic mixture; b) contacting a titanium-containing compound with the acidic mixture to form a titanium treatment solution; c) contacting a pre-formed chrominated silica-support comprising from about 0.1 wt. % to about 20 wt. % water with the titanium treatment solution to form a pre-catalyst; and d) thermally treating the pre-catalyst to form the catalyst.

A method of preparing a catalyst comprising a) contacting a non-aqueous solvent, a carboxylic acid, and a chromium-containing compound to form an acidic mixture; b) contacting a titanium-containing compound with the acidic mixture to form a titanium treatment solution; c) contacting a pre-formed silica-support comprising from about 0.1 wt. % to about 20 wt. % water with the titanium treatment solution to form a pre-catalyst; and d) thermally treating the pre-catalyst to form the catalyst. A method of preparing a catalyst comprising a) contacting a non-aqueous solvent and a carboxylic acid to form an acidic mixture; b) contacting a titanium-containing compound with the acidic mixture to form a titanium treatment solution; c) contacting a pre-formed chrominated silica-support comprising from about 0.1 wt. % to about 20 wt. % water with the titanium treatment solution to form a pre-catalyst; and d) thermally treating the pre-catalyst to form the catalyst.

Various methods of reshaping and recycling thermoset polymers and composites containing thermoset polymers are provided. The methods involve the bond exchange reaction of exchangeable covalent bonds in the polymer matrix with a suitable small molecule solvent in the presence of a catalyst. In some aspects, the methods are applied to a carbon fiber reinforced polymer or a thermoset polymer where the thermoset polymer matrix includes a plurality of ester bonds. Using a small molecule alcohol, the methods provide for recycling one or both of the carbon fiber and the polymer, for welding two surfaces, or for repairing a damaged surface in the materials.

Various methods of reshaping and recycling thermoset polymers and composites containing thermoset polymers are provided. The methods involve the bond exchange reaction of exchangeable covalent bonds in the polymer matrix with a suitable small molecule solvent in the presence of a catalyst. In some aspects, the methods are applied to a carbon fiber reinforced polymer or a thermoset polymer where the thermoset polymer matrix includes a plurality of ester bonds. Using a small molecule alcohol, the methods provide for recycling one or both of the carbon fiber and the polymer, for welding two surfaces, or for repairing a damaged surface in the materials.

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below ##STR00001## where R.sup.x is cationic initiator residue; R.sup.a is a polyolefin group; R.sup.1 and R.sup.2 are each, independently in each —(CR.sup.1R.sup.2) unit, H, alkyl, alkoxy, or alkylaryl; R.sup.3 and R.sup.4 are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below ##STR00001## where R.sup.x is cationic initiator residue; R.sup.a is a polyolefin group; R.sup.1 and R.sup.2 are each, independently in each —(CR.sup.1R.sup.2) unit, H, alkyl, alkoxy, or alkylaryl; R.sup.3 and R.sup.4 are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.