PROPENE POLYMERIZATION WITH MGCL2-SUPPORTED TICL4/DIOCTYLPHTHALATE CATALYST .2. EFFECTS OF POLYMERIZATION CONDITIONS ON THE MICROSTRUCTURE OF ISOTACTIC POLYMER

摘要

Propene was polymerized over the MgCl2-supported TiCl4/dioctylphthalate catalyst in heptane. Polymer products obtained under different polymerization conditions were separated into isotactic and atactic polypropenes by the extraction of boiling n-heptane. The effects of polymerization time, cocatalyst type, cocatalyst/catalyst ratio, polymerization temperature, and external base/cocatalyst ratio on the isotactic triad of the isotactic portion of polypropene were investigated. 2,2,6,6-Tetramethyl piperidine (TMPIP), dimethoxy diphenyl silane (DMDPS), and t-butylmethyl ether (TBME) were employed as the external Lewis base. High concentrations of the first two bases caused a decrease in isotactic triads in the isotactic polymer, while TBME showed no significant effects. The difference can be attributed to the different roles these external bases play in polymerization. (C) 1995 John Wiley & Sons, Inc. [References: 26]