Hyperbranched block copolymer from AB2 macromonomer: Synthesis and its reaction-induced microphase separation in epoxy thermosets

In this contribution, we reported the synthesis of a hyperbranched block copolymer composed of poly(ε-caprolactone) (PCL) and polystyrene (PS) subchains. Toward this end, we first synthesized an α-alkynyl- and ω,ω′-diazido-terminated PCL- b -(PS) 2 macromonomer via the combination of ring-opening polymerization and atom transfer radical polymerization. By the use of this AB 2 macromonomer, the hyperbranched block copolymer ( h -[PCL- b -(PS) 2 ]) was synthesized via a copper-catalyzed Huisgen 1,3-dipolar cycloaddition (i.e., click reaction) polymerization. The hyperbranched block copolymer was characterized by means of 1 H nuclear magnetic resonance spectroscopy and gel permeation chromatography. Both differential scanning calorimetry and atomic force microscopy showed that the hyperbranched block copolymer was microphase-separated in bulk. While this hyperbranched block copolymer was incorporated into epoxy, the nanostructured thermosets were successfully obtained; the formation of the nanophases in epoxy followed reaction-induced microphase separation mechanism as evidenced by atomic force microscopy, small angle X-ray scattering, and dynamic mechanical thermal analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54 , 368–380