Controllable design of nanostructure in block copolymer reinforced epoxy composites

ABSTRACT The modification of epoxy composites through the construction of nanostructures via the self‐organization of block copolymers in epoxy has become a hot topic. In this research, polystyrene‐ b ‐poly(ɛ‐caprolactone)‐ b ‐polydimethylsiloxane‐ b ‐poly(ɛ‐caprolactone)‐ b ‐polystyrene (PS‐PCL‐PDMS‐PCL‐PS) block copolymers with different lengths of PS subchains were synthesized and incorporated into epoxy thermoset. Due to the difference in the length of PS subchains, two different sizes of core‐shell nanostructures were obtained. When these two block copolymers were incorporated into epoxy, the tensile strength, elongation at break, damping temperature in range (tan δ > 0.2), and storage modulus of the epoxy thermoset below 105 °C were simultaneously improved. Meanwhile, the effects of the lengths of PS subchains on the size of nanostructures and the relationship between microstructure and macroscopic properties of epoxy composites were systematically investigated. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46362.