The propagation rate constants of the cationic polymerization of alkenes—part III. Indene, two vinyl ethers and general discussion

On the propagation rate constants of cationic polymerizations

“…If that line had been followed since the discovery of this type of initiator,12, 13 an enormous amount of pointless work yielding highly equivocal results4 would have been avoided 14 Do use at least two different cations and two different anions to find out whether the results are vitiated by any special effects. Don't use unstable anions, such as SbCl, that decompose easily. Don't use reactive anions, such as those from any protonic acid, that can form esters and conjugate anions. Do, if you are using a new alkenic monomer, ascertain that the cation actually adds to the monomer as required and is not forming an ion by abstracting something from the monomer. Don't “kill” the reaction mixtures with an alkanol. Do neutralize the propagators with an easily identifiable hydroxyl or amino compound that combines with the polymer so that the number of chain ends can be counted. Do measure the impurity levels in solvents and monomers by functional tests 15, 16 Do record the electrical conductivity of the reaction mixture during and after the polymerization.…”