Just wanting to vent.... (2 Viewers)

Joe OKC

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The types of the compound catalyst systems primarily include metallocene/metallocene compound catalyst systems and metallocene/Ziegler-Natta compound catalyst systems, with the latter being particularly preferred. By compounding a metallocene catalyst with a Ziegler-Natta catalyst, it is possible to overcome the disadvantages of the metallocene catalyst system, such as a single active center, narrow molecular weight distribution of the resulting polymers and poor processability, while maintaining its advantages, such as good stereoregularity of the resulting polymers, good copolymerizability and the like. For example, European Patent Application Publication 0 447 070 A1 discloses a solid catalyst suitable for polymerizing olefins in a heterogeneous process, comprising (1) a solid support containing from 80 to 99.5 mol % of magnesium dichloride and from 0.5 to 20 mol % of an electron-donor compound free from labile hydrogen, (2) an electron-donor compound containing labile hydrogen, (3) a zirconium metallocene, (4) at least one halide of a transition metal chosen from titanium and vanadium, and (5) an organoaluminum compound, preferably an aluminoxane compound. The catalyst disclosed therein is prepared by supporting zirconium and titanium or vanadium onto the support formed from magnesium dichloride and is suitable for the heterogeneous polymerization of olefins, and however, such a catalyst has a relatively low activity and the molecular weight distribution (Mw/Mn) of the resulting polymer is only about 4, which is still relatively narrow. European Patent Application Publication 0 447 071 A1 discloses a compound solid catalyst suitable for polymerizing olefins, comprising (1) a support containing from 90 to 99.9mol % of magnesium dichloride and from 0.1 to 10 mol % of an electron-donor compound free from labile hydrogen, (2) a zirconium metallocene, (3) at least one halide of a transition metal chosen from titanium and vanadium, and (4) an organoaluminum compound, preferably an aluminoxane compound. The catalyst disclosed therein is prepared by supporting zirconium and titanium or vanadium onto the support formed from magnesium dichloride and is suitable for the heterogeneous polymerization of olefins, and can produce polymers having better particle morphology (Dm/Dn: 1.5; bulk density: 0.3-0.4 g/cm3). Although such a catalyst has a higher ratio of Zr to Ti, for example from 2 to 20, it has a relatively low activity and the molecular weight distribution (Mw/Mn) of the resulting polymer is only about 5, which is still relatively narrow. The reason may be that part of zirconium supported is inactive for being covered, thus decreasing the activity of the whole catalyst.
 
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You had me at compound catalyst. No really, you did. You had me thoroughly confused by that point.
 
Looks like Callaway Golf has a new driver coming soon....
 
A cleaner, more environmentally friendly laundry detergent?

Just another step towards removing hydrocarbon based polymers from our society.

Check surfactant systems.

Good find, Joe.
 
joe, I thought this was gonna be another striper story. WTH I thought you were a strip club manager not a rocket scientist. now I wonder.
 
joe, I thought this was gonna be another striper story. WTH I thought you were a strip club manager not a rocket scientist. now I wonder.

fintalk-striper1.jpg


:idunno:
 

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