Kinetic investigations of polymerization of methyl methacrylate with zirconocenes.
The polymn. of Me methacrylate (MMA) in toluene with Cp2ZrMe2-Ph3C+B(C6F5)4- as initiating system was kinetically investigated. This system can be regarded as a combination of the systems described by Collins and Soga. Only if the catalysts' ratio was >1, monomer conversions of more than 99% and polymers with no.-av. mol. wts. higher than 200,000 and polydispersities 1.5-1.6 were obtained. From a kinetic anal. of time-conversion curves using the software package Predici, it can be deduced that the mechanism is consistent with that proposed by Collins et al. However, the mechanism has to be extended by incorporating a first-order termination reaction of the active species. Rate coeffs. of all elementary reactions were detd. from time-conversion curves. The kinetic investigations were accompanied by ab initio calcns., which support the assumed kinetic model. ZrCl.
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