Triblock copolymers encompassing a hard-soft-hard architecture are widely used as
thermoplastic elastomers (TPE), a group of materials gaining increasing industrial and
academic interest since its inception in the 1950s. Early prominent examples produced
by living anionic polymerization employ a styrenic hard block and a soft block using
butadiene (SBS) or isoprene (SIS) as monomers. TPEs comprised of acrylic monomers
have been explored as alternatives, due to their improved oxidation resistance and
optical clarity. This was promoted by the advent of controlled radical polymerization
(CRP), offering new options for synthesis of block copolymeric architectures.
Besides more established CRP methods, reversible complexation mediated
polymerization (RCMP) is a new emerging CRP. The polymerization is controlled by
reversibly activating iodine capped polymers through an organic catalyst. The method
offers a low barrier of entry, due to necessary materials being commercially widely
available and relatively inoffensive towards health or the environment. Since its discovery,
RCMP has demonstrated its strong capabilities in the polymerization of (meth)acrylic
monomers.
In this work, we investigate the synthesis of acrylic ABA block copolymers featuring a
hard-soft-hard architecture using RCMP. Using a bifunctional organoiodide as an RCMP
initiator, allows for the two-step synthesis of the desired triblock copolymers. Synthesis
conditions for the soft block and the subsequent chain extension were explored, focusing
on striking balance between attaining high molecular weights, reaching high monomer
conversions and shortening reaction times. We further examined mechanical properties
and microphase separation of the produced copolymers.