In situ polarity functionalization and properties of styrenic triblock copolymers synthesized via RAFT emulsion polymerization

The in situ polarity functionalization of the styrenic triblock copolymers was accomplished via the block introduction of polar monomer, n-butyl acrylate, with the help of reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization. The polarity functionalization, microphase separation, static and dynamic mechanical properties, water resistance, transparency, and thermal stability of the synthesized polarity-functionalized triblock copolymers, polystyrene-block-poly(n-butyl acrylate)-block-polystyrene (SAS), were extensively studied. The poly(n-butyl acrylate) (PBA) middle block higher than 10 wt % has the favorable toughening effect on polystyrene (PSt) two-end block due to the microphase separation in SAS. The glass transition of the continuous plastic phase (mainly composed of PSt block) has a much greater influence on the storage modulus than that of the dispersed rubber phase (mainly composed of PBA block). The polarity-functionalized SAS has good water resistance, high transparency, and robust thermal stability. The polarity-functionalized SAS will have such a potential application broadening as polar adhesive. (C) 2016 Wiley Periodicals, Inc.