The University of Akron

Tibor Pernecker

Joseph P Kennedy

Bela Ivan

Joseph F Kennedy

The dispersion polymerization of isobutylene includes a dispersing agent. The dispersing agent is a compound having a CO.sub.2 -phobic moiety and at least one CO.sub.2 -philic moiety. The CO.sub.2 -phobic moiety is polysibutylene-philic. Novel polymerization initiators are organometallic.

Method, dispersing agent and initiator for the dispersion polymerization

A process is disclosed for carbocationically polymerizing monomers having one or more carbon-carbon double bonds in a medium primarily of carbon dioxide at or above 31.1.degree. C. and at or above 73 bars pressure. The supercritical carbon dioxide can replace traditional solvents for carbocationic polymerizations. While traditional solvents like methylene chloride do not function to allow polymers to form above cryogenic temperatures, it has been found that polymers can be formed at higher temperatures in this supercritical medium.

Carbocationic polymerizations in supercritical CO.sub.2

The synthesis of poly(isobutylene-b-methyl vinyl ether) (PIB-b-PMeVE) by living carbocationic polymerization (LC.sym.Pzn) employing the sequential monomer addition (SMA) technique is described. The process starts by producing the living PIB.sym. block employing the 2-chloro-2,4,4-trimethylpentane (TMPC11/TiCl.sub.4 initiating system in the presence of the common ion salt tetra-n-butylammonium chloride (n-Bu.sub.4 NCl) in CH.sub.3 Cl/n-C.sub.6 H.sub.14 or CH.sub.2 Cl.sub.2 /n-C.sub.6 H.sub.14 mixed solvents at -80.degree. C. and continues by the addition of methyl vinyl ether (MeVE). The second living block forms only in the presence of excess TiCl.sub.4 suggesting that the species that starts the second block and subsequently sustains its growth is a MeVE.multidot.TiCl.sub.4 complex. The stoichiometry of this complex (1:1 or 1:2) is uncertain. The TiCl.sub.4 remains attached to the MeVE units after their incorporation into the diblock, however, it can be readily removed by water. PMeVE obtained in the presence of excess TiCl.sub.4 degrades by dealcoholation, however, degradation is prevented by the use of n-Bu.sub.4 NCl. Various length (composition) diblocks have been prepared and characterized. The novel PIB-b-PmeVE's exhibit strongly amphiphilic character.

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Akron, OH, United States of America

Tibor Pernecker