The possibilities of increasing the livingness in cationic isobutylene
polymerizations has been investigated. It has been assumed that the l
iving chain-end is polarized but non-dissociated and relatively stable
, therefore, i) shifting of the dissociation equilibrium by adding sal
ts with common or non-common anion in excess, and ii) increasing of th
e stability of the chain-end by complexing it with electrondonors, may
increase the livingness of the system. indeed, the addition of n-Bu 4
NCl or n-Bu4NI to systems with BCl3 or TiCl4 coinitiators, as well as
the addition of dimethyl sulphoxide as electrondonor in a broad concen
tration range, improved the living character. The possibility of compl
exation of the chain-end by the monomer has also been supported.