Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers prepared via controlled free-radical miniemulsion polymerization using degenerative iodine transfer
C. Farcet et al., Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers prepared via controlled free-radical miniemulsion polymerization using degenerative iodine transfer, MACRO RAPID, 21(13), 2000, pp. 921-926
Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl ac
rylate)-co-styrene] block copolymers were prepared in an aqueous dispersed
system via controlled free-radical miniemulsion polymerization using degene
rative iodine transfer. The first step is patch miniemulsion polymerization
of styrene in the presence of C6F13I as transfer agent. The second step co
nsists of the addition of butyl acrylate to this seed latex, either in one
shot or continuously. The addition was started before the consumption of st
yrene was complete in order to perform a copolymerization reaction able to
moderate the rate of propagation in the butyl acrylate polymerization step
and, therefore, to favor the transfer reaction. Kinetics of polymerization
and control of the molar masses were examined according to the experimental
conditions and particularly to the rate of butyl acrylate addition. The fo
rmed block copolymers were analyzed by size exclusion chromatography (SEC),
differential scanning calorimetry (DSC) and nuclear magnetic resonance (NM
R).