| Abstract: | A general approach to a transfer-suppressed proceeding of cationic vinyl polymerization is put forward. The fundamental principle of the method consists in stabilization of the counter-ion by interaction with acceptors. This results in an orbital controlled cation-anion interaction and by this, suppression of side reactions, for example chain transfer due to lowering the ß-hydrogen acidity of the growing cation and the specific monomer solvation of the propagation transition state. It is shown that picric acid, initiated polymerization of p-methoxyatyrene and vinyl ethers, runs free of transfer in contrast to LEWIS-acid initiated systems. Cationic polymerization, initiated by iodine based systems, are in the same category as demonstrated by molecular weight distributions, monomer addition experiments, thermokinetical data and UV-spectroscopical measurements. The results are discussed in the framework of a general energetic scheme of propagation via cation-anion orbital controlled interactions with propagating ion pairs. |
