摘要 |
External donor systems, catalyst systems and olefin polymerization processes are described herein. The external donor systems generally include a first external donor represented by the general formula SiR<SUP>2</SUP><SUB>m</SUB>(OR<SUP>3</SUP>)<SUB>4-m</SUB>, wherein each R<SUP>2 </SUP>is independently selected from alkyls, cycloalkyls, aryls and vinyls, each R<SUP>3 </SUP>is independently selected from alkyls and m is from 0 to 4. The external donor systems further include a second external donor represented by the general formula SiR<SUP>4</SUP><SUB>m</SUB>(OR<SUP>5</SUP>)<SUB>4-m</SUB>, wherein each R<SUP>4 </SUP>is independently selected from alkyls, cycloalkyls, aryls and vinyls, each R<SUP>5 </SUP>is independently selected from alkyls, m is from 0 to 4 and at least one R<SUP>4 </SUP>is a C<SUB>3 </SUB>or greater alkyl.
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