Polyisobutylene-containing block polymers by sequential monomer addition. I. The living carbocationic polymerization of styrene

Authors

  • G. Kaszas,

    1. The University of Akron, Institute of Polymer Science, Akron, Ohio 44325-3909
    Current affiliation:
    1. Polymer Rubber Co., Sarnia, Ontario, Canada
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  • J. E. Puskas,

    1. The University of Akron, Institute of Polymer Science, Akron, Ohio 44325-3909
    Current affiliation:
    1. Polymer Rubber Co., Sarnia, Ontario, Canada
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  • J. P. Kennedy,

    Corresponding author
    1. The University of Akron, Institute of Polymer Science, Akron, Ohio 44325-3909
    • The University of Akron, Institute of Polymer Science, Akron, Ohio 44325-3909
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  • W. G. Hager

    1. The University of Akron, Institute of Polymer Science, Akron, Ohio 44325-3909
    Current affiliation:
    1. Owens/Corning Fiberglas, Granville, Ohio
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  • Paper XL in the series “Living Carbocationic Polymerization.”

Abstract

The living carbocationic polymerisation of styrene (St) has been investigated by the 2-chloro-2,4,4-trimethylpentane (TMPCI)/TiCl4 initiating system in the presence of various additives such as electron pair donors (EDs) and the proton trap 2,6-di-tert-butylpyridine (DtBP) by the use of the mixed solvent CH3Cl/methyl-cyclohexane (MCHx) (40/60 v/v) at −80°C under conventional laboratory conditions. The TMPCl/TiCl4 system in the absence of additives produces ill-defined bimodal molecular weight distribution (MWD) polymers. Much better defined polystyrenes (PSt) can be obtained in the presence of EDs, such as N,N-dimethylacetamide (DMA) and hexamethylphosphoramide (HMPA). Monomer depletion should be avoided to prevent intra- or intermolecular alkylation yielding indanyl end groups or branched polymers, respectively. In the combined presence of an ED and the proton trap, i.e., DMA + DtBP, the living polymerization of St has been achieved and thus the foundations for the carbocationic synthesis of PSt block polymers by sequential monomer addition have been laid.

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