Mechanical properties of block copolymer vesicle and micelle modified epoxies

Jennifer M. Dean, Robert B. Grubbs, Walid Saad, Robert F. Cook, Frank S. Bates

Research output: Contribution to journalArticle

184 Scopus citations

Abstract

Block copolymers with and without reactive functionalities can improve fracture resistance in brittle epoxies even when added in relatively small amounts (<5 wt%). At certain compositions, amphiphilic block copolymers spontaneously self-assemble into vesicles, spherical micelles, or wormlike micelles in thermoset resins, and these morphologies are retained with the full curing of the resins. The addition of such block copolymers leaves the glass-transition temperature of these blends relatively unchanged, whereas the fracture resistance increases up to a factor of 3.5 for the vesicle-modified blends. For epoxies modified with block copolymers self-assembled into a spherical geometry (vesicles or spherical micelles), the fracture resistance scales with the ratio of the interparticle distance to the average vesicle (or spherical micelle) diameter (Di/Dp) and increases as this quantity is reduced. Greater adhesion between the vesicle and epoxy resin improves the fracture resistance only at higher values of Di/Dp, at which the materials are more brittle. Debonding and subsequent matrix plastic deformation are identified as the toughening mechanisms in these blends.

Original languageEnglish
Pages (from-to)2444-2456
Number of pages13
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume41
Issue number20
DOIs
StatePublished - Oct 15 2003

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Keywords

  • Block copolymers
  • Epoxies
  • Fracture
  • Toughness
  • Vesicles

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Chemistry

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