Epoxy toughening with nano-sized amphiphilic block copolymer micelles Conference Paper uri icon

abstract

  • An amphiphilic poly(ethylene-alt-propylene)-b-poly(ethylene oxide) (PEP-PEO) block copolymer (BCP) was blended with a bisphenol A-based epoxy resin formulation and self-assembled into a worm-like micelle structure. With an incorporation of 5 wt% of the BCP material, the fracture toughness was improved by more than 100% over the neat epoxy. The morphology and mechanical properties of this BCP-modified epoxy were investigated using transmission electron microscopy (TEM) and fracture toughness measurements. Toughening mechanisms from the worm-like micelle modified material were investigated using the double-notch four-point-bending (DN-4PB) technique, and the results are compared to data obtained from the same epoxy thermoset formulation containing a BCP that self-assembled into spherical micelles. Elongated cylindrical micelles produce improved toughness, which is interpreted based on a combination of mechanisms including crack tip blunting, cavitation, particle debonding, limited shear yielding, and crack bridging. The implications of the present study for polymer toughening in general are also discussed.

author list (cited authors)

  • Liu, D., Sue, H. J., Thompson, Z. J., Bates, F. S., & Hillmyer, M. A.

publication date

  • August 2013