Catalysts for control of long chain branching
Catalyst systems and methods for making and using the same are disclosed. A catalyst composition is provided that includes a catalyst compound supported to form a supported catalyst system, the catalyst compound including: where each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and X are as discussed herein.
1. A method of polymerizing olefins to produce a polyolefin with control over long chain branching, comprising contacting ethylene and a comonomer with a catalyst system, wherein the catalyst system comprises a catalyst compound selected from the group consisting of:
and mixtures thereof;
wherein each X is independently a leaving group selected from a halogen, a labile hydrocarbyl, a substituted hydrocarbyl, or a heteroatom group.
2. The method of claim 1 , comprising forming a product from the polyolefin.
3. The method of claim 1 , comprising combining the catalyst compound with another catalyst compound on a support to form a commonly supported catalyst system.
4. The method of claim 1 , comprising:
measuring a sample of the polyolefin to obtain an initial product property; and
changing a process parameter to obtain a second product property, based, at least in part, on the initial product property.
5. The method of claim 4 , wherein measuring a sample of the polyolefin comprises measuring comonomer incorporation as a function of a molecular weight.
6. The method of claim 4 , wherein measuring a sample comprises determining a physical property of a plastic sample prepared from the polyolefin.
7. The method of claim 4 , wherein measuring a sample comprises determining a flow index (I 21 ), a melt index I 2 , a ratio of two melt indices, a density, a molecular weight distribution, a comonomer content, or any combinations thereof.
8. The method of claim 4 , wherein changing a process parameter comprises adjusting a reactor temperature.
9. The method of claim 4 , wherein changing a process parameter comprises adjusting an ethylene partial pressure.
10. The method of claim 4 , comprising adjusting a ratio of the comonomer to ethylene within a polymerization reactor to control a composition distribution, a molecular weight distribution, a melt index (I 2 ), or a ratio of two melt indices, or any combinations thereof, of the polyolefin.
11. The method of claim 4 , comprising adjusting a ratio of hydrogen to ethylene within a polymerization reactor to control a composition distribution, a molecular weight distribution, a melt index (I 2 ), or a ratio of two melt indices, or any combinations thereof, of the polyolefin.