The cationic ring-opening polymerization of 2-oxazolines is known to b
e initiated by alkyl halides, Lewis acids and esters of strong acids.
The polymerization proceeds by a living mechanism. Numerous block and
graft copolymers have already been described. Recently it was found th
at chloroformates (R-O-CO-Cl) are also useful initiators. The mechanis
m of the initiation and propagation is discussed. This type of initiat
ors allows the synthesis of different novel two-block and three-block
copolymers, star-shape polymers, and a graft copolymer with a polyviny
lacetate backbone.