1 research outputs found
Amphiphilic Block Copolymers as Stabilizers in Emulsion Polymerization: Effects of the Anchoring Block Molecular Weight Dispersity on Stabilization Performance
Poly(sodium acrylate)-<i>b</i>-polystyrene block copolymers were employed as stabilizers in the
emulsion polymerization of styrene. Previous work by our group has
shown that the molecular weight dispersity of the stabilizing block
is an important design parameter of block copolymer stabilizers; herein,
the molecular weight dispersity of the anchoring polystyrene block, <i>Đ</i><sub>PS</sub>, was investigated. Stabilization performance
was evaluated by the critical aggregation concentration, aggregation
number, and surface activity of the block copolymers and the size,
distribution, and zeta potential of the polystyrene latex particles.
It was observed that <i>Đ</i><sub>PS</sub> had a strong
effect on aggregation number, which led to a change in the number
of latex particles in the seeded emulsion polymerization of styrene.
Surface activity decreased with increasing <i>Đ</i><sub>PS</sub> due to a greater diversity of copolymer compositions,
supporting the idea that copolymers of different composition play
different roles in the stabilization of an emulsion. The performance
of block copolymer stabilizers, evaluated by the stability and size
distribution of latex particles, was indistinguishable over the range
of <i>Đ</i><sub>PS</sub> studied; narrow stabilizer
molecular weight distributions were not necessary for satisfactory
performance