Living cationic polymerization of cis‐ and trans‐ethyl propenyl ethers and synthesis of block copolymers with isobutyl vinyl ether

Abstract The cationic polymerization of cis‐ and trans‐ethyl propenyl ethers (EPE, CH3CHCHOC2H5), initiated by a mixture of hydrogen iodide and iodine (HI/I2 initiator) at −40°C in nonpolar media (toluene and n‐hexane), led to living polymers of controlled molecular weights and a narrow molecular weight distribution (MWD) (M̄w/M̄n = 1.2–1.3). The geometrical isomerism of the monomer did not affect the living character of the polymerization. 13C NMR stereochemical analysis of the polymers showed that the living propagating end is sterically less crowded than nonliving counterparts generated by conventional Lewis acids (e.g., BF3OEt2). New block copolymers between EPE (cis or trans) and isobutyl vinyl ether were also prepared by sequential living polymerization of the two monomers.