Effect of Hydrogen and External Donor on Propylene Polymerization Kinetics with a 4th-Generation Ziegler-Natta Catalyst

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Abstract

Apparent kinetic rate constants and activation energies for catalyst activation, deactivation, and propylene propagation with a 4th-generation Ziegler-Natta catalyst are estimated. The rate of polymerization in the presence of donor and hydrogen is higher than in their absence. Catalyst activation and propagation rate constants increase with the addition of hydrogen, likely because hydrogen frees 2–1-terminated dormant sites. The deactivation term was the highest without electron donor, presumably because the nonspecific sites deactivate faster than the specific sites. Apparent activation energies for catalyst activation, deactivation, and propagation are not significantly influenced by the presence of hydrogen or external donor, indicating that they do not affect these mechanisms substantially.

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