A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of the reactor feed stream, wherein the reactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the reactor feed stream into a concentration of the solid component in the reactor feed stream. A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of a precontactor feed stream, wherein the precontactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the precontactor feed stream into a concentration of the solid component in a precontactor effluent stream, wherein the precontactor effluent stream comprises the reactor feed stream.

A complex of formula (I): (I′) M is Hf; each X is a sigma ligand; L is a bridge of formula -(ER.sup.8.sub.2).sub.y—; y is 1 or 2; E is C or Si; each R.sup.8 is independently a C.sub.1-C.sub.20-hydrocarbyl, tri(C.sub.1-C.sub.20-alkyl)silyl, C.sub.6-C.sub.20- aryl, C.sub.7-C.sub.20-arylalkyl or C.sub.7-C.sub.20-alkylaryl or L is an alkylene group such as methylene or ethylene; Ar and Ar′ are each independently an aryl or heteroaryl group optionally substituted by 1 to 3 groups R.sup.1 or R.sup.1′ respectively; R.sup.1 and R.sup.1′ are each independently the same or can be different and are a linear or branched C.sub.1-C.sub.6-alkyl group, C.sub.7-20 arylalkyl, C.sub.7-20 alkylaryl group or C.sub.6-20 aryl group with the proviso that if there are four or more R.sup.1 and R.sup.1′ groups present in total, one or more of R.sup.1 and R.sup.1′ is other than tert butyl; R.sup.2 and R.sup.2′ are the same or are different and are a CH.sub.2—R.sup.9 group, with R.sup.9 being H or linear or branched C.sub.1-C.sub.6-alkyl group, C.sub.3-8 cycloalkyl group, C.sub.6-10 aryl group; each R is a —CH.sub.2—, —CHRx- or C(Rx).sub.2-group wherein Rx is C.sub.1-4 alkyl and where m is 2-6; R.sup.5 is a linear or branched C.sub.1-C.sub.6-alkyl group, C.sub.7-20 arylalkyl, C.sub.7-20 alkylaryl group or C.sub.6-C.sub.20-aryl group; R.sup.6 is a C(R.sup.10).sub.3 group, with R.sup.10 being a linear or branched C.sub.1-C.sub.6 alkyl group; and R.sup.6 and R.sup.7′ are the same or are different and are H or a linear or branched C.sub.1-C.sub.6-alkyl group. Invention relates also to a catalyst in solid form comprising (i) a complex of formula (I) and (ii) a cocatalyst of an aluminium compound and (iii) a cocatalyst of a boron compound.

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Disclosed are support-activators and catalyst compositions comprising the support-activators for polymerizing olefins in which the support-activator includes clay heteroadduct, prepare from a colloidal phyllosilicate such as a colloidal smectite clay, which is chemically-modified with a heterocoagulation agent. By limiting the amount of heterocoagulation reagent relative to the colloidal smectite clay as described herein, the smectite heteroadduct support-activator is a porous and amorphous solid which can be readily isolated from the resulting slurry by a conventional filtration process, and which can activate metallocenes and related catalysts toward olefin polymerization. Related compositions and processes are disclosed.

Catalyst compositions containing a metallocene compound, a solid activator, and a co-catalyst, in which the solid activator or the supported metallocene catalyst has a d50 average particle size of 15 to 50 μm and a particle size distribution of 0.5 to 1.5, can be contacted with an olefin in a loop slurry reactor to produce an olefin polymer. A representative ethylene-based polymer produced using the catalyst composition has excellent dart impact strength and low gels, and can be characterized by a HLMI from 4 to 10 g/10 min, a density from 0.944 to 0.955 g/cm.sup.3, a higher molecular weight component with a Mn from 280,000 to 440,000 g/mol, and a lower molecular weight component with a Mw from 30,000 to 45,000 g/mol and a ratio of Mz/Mw ranging from 2.3 to 3.4.

Methods for determining the catalytic activity of an activated chemically-treated solid oxide using a color measurement technique are described, and these methods are integrated into transition metal-based catalyst preparation processes and systems, as well as into olefin polymerization processes and related polymerization reactor systems.

Disclosed herein are ethylene-based polymers generally characterized by a melt index of less than 1 g/10 min, a density from 0.93 to 0.965 g/cm.sup.3, a CY-a parameter at 190° C. of less than 0.2, an average number of short chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 40,000 to 60,000 g/mol, and an average number of long chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 4,000,000 to 6,000,000 g/mol. The ethylene polymers can be used to fabricate pipes, blown films, and blow molded products, and the ethylene polymers can be produced with a dual catalyst system containing a single atom bridged or two carbon atom bridged metallocene compound with two indenyl groups or an indenyl group and a cyclopentadienyl group, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group with an alkenyl substituent.

Ethylene-based polymers are characterized by a density from 0.92 to 0.955 g/cm.sup.3, a HLMI of less than 35 g/10 min, and a ratio of a number of short chain branches (SCBs) per 1000 total carbon atoms at Mz to a number of SCBs per 1000 total carbon atoms at Mn in a range from 11.5 to 22. These polymers can have a higher molecular weight (HMW) component and a lower molecular weight (LMW) component, in which a ratio of a number of SCBs per 1000 total carbon atoms at Mn of the HMW component to a number of SCBs per 1000 total carbon atoms at Mn of the LMW component is in a range from 10.5 to 22. These ethylene polymers can be produced using a dual catalyst system containing an unbridged metallocene compound with an indenyl group having at least one halogen-substituted hydrocarbyl substituent with at least two halogen atoms, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group.

Ethylene-based polymers are characterized by a density from 0.92 to 0.955 g/cm.sup.3, a HLMI of less than 35 g/10 min, and a ratio of a number of short chain branches (SCBs) per 1000 total carbon atoms at Mz to a number of SCBs per 1000 total carbon atoms at Mn in a range from 11.5 to 22. These polymers can have a higher molecular weight (HMW) component and a lower molecular weight (LMW) component, in which a ratio of a number of SCBs per 1000 total carbon atoms at Mn of the HMW component to a number of SCBs per 1000 total carbon atoms at Mn of the LMW component is in a range from 10.5 to 22. These ethylene polymers can be produced using a dual catalyst system containing an unbridged metallocene compound with an indenyl group having at least one halogen-substituted hydrocarbyl substituent with at least two halogen atoms, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group.

Methods for preparing a metallocene-based catalyst composition that can impact the long chain branching of ethylene homopolymers and copolymers produced using the catalyst composition are described. The catalyst composition can be prepared by contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution, and then contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition.

The present disclosure provides novel unbridged group 4 indacenyl-containing metallocene compounds. The catalyst system may be used for olefin polymerization processes.