| 摘要 |
In an ongoing process for the production of polypropylene polymer, propylene monomer is contacted with a polypropylene polymerization catalyst under polymerization conditions in the presence of molecular hydrogen to control polymer molecular weight and polymer properties such as melt flow. Production of polymer having increased or decreased melt flow is achieved by contacting at least a portion of the recycle gas with a metal hydride or metal hydride precursor under conditions whereby the hydrogen concentration of the recycle gas and thus the polymerization reactor is increased or decreased, respectively. The increase or decrease in hydrogen concentration in the polymerization reactor results in production of polypropylene polymer product of higher or lower melt flow.
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