The stability of living polyisobutylene chains obtained by the 1,3-di(2-chloro-2-propyl)-5-tert-butylbenzene (tBuDiCumCl)/TiCl4 initiating system was investigated under monomer starved conditions (100% monomer conversion) in the absence and presence of different additives, such as N,N-dimethylacetamide (DMA), 2,6-di-tert-butylpyridine (DtBP), pyridine (Py) and 2,4-dimethylpyridine (DMPy), in CH2Cl2/hexane (40:60 v/v) mixture at -78°C. With the exception of DtBP, all the additives resulted in unexpected stability of the propagating carbocationic species in these systems. Only negligible amounts of chain ends with expected double bonds were formed as verified by 1H NMR. However, molecular weight data suggest that there is difference in the effect of the examined nucleophilic compounds in their mode of action during living polymerization of isobutylene. It is concluded that the currently existing mechanistic propositions cannot satisfactorily explain experimental results of living isobutylene polymerization.
|Number of pages||2|
|Journal||American Chemical Society, Polymer Preprints, Division of Polymer Chemistry|
|Publication status||Published - Mar 1 1996|
ASJC Scopus subject areas
- Polymers and Plastics