ESR study on styrene polymerization with CpTiCl3/MMAO: Effect of monomer addition on catalyst activity

✍ Scribed by Y. H. Huang; W.-J. Wang; S. Zhu; G. L. Rempel

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 162 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990815)37:16<3385::aid-pola37>3.0.co;2-e

✦ Synopsis

An on-line electron spin resonance (ESR) technique was applied to investigate the syndiospecific polymerization of styrene activated by the catalyst system CpTiCl 3 /MMAO. The measurements included trivalent titanocene concentration and monomer conversion. The activation procedure was found to have a dramatic effect on catalyst activity. Adding the reactants in the order of (MMAO ϩ CpTiCl 3 ) ϩ St gave a much higher trivalent titanocene concentration and catalyst activity than the order of (MMAO ϩ St) ϩ CpTiCl 3 . The catalyst deactivation behaviors in the temperature range of 25-70°C were followed as a function of time during polymerization. At high Al/Ti ratios (500 -1000), the decay rates of trivalent titanocene in the presence of styrene were much faster than those of the pure catalyst system.