NEW ELECTRON BEAM CURABLE POLYMERS WITH HIGH ADHESION AND TOUGHNESS

Abstract

The purpose of this Cooperative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory (ORNL) (UT-Battelle, LLC - Contractor) and The Boeing Company (Boeing) and Battelle Memorial Institute (Battelle) is to develop new furan-like, electron beam curable epoxies with better properties than existing electron beam curable epoxies. Boeing and ORNL are historically leaders in the development and application of electron beam curable polymer composites. Boeing and ORNL have led two large collaborative projects that developed the base technology and addressed mechanical properties. While very significant progress was made in these projects, the toughness and interfacial shear strength of electron beam curable composites remains deficient in comparison with the industry benchmark thermally cured epoxies such as Cytec 977-3 and Hexcel 8552. Recently Lee and Palmese found that electron beam curable epoxy could be substantially toughened by copolymerization with tetrahydrofuran, with modest increase in short beam shear strength and very little reduction in glass transition temperature. Battelle has unique expertise in furan-like polymer chemistry, especially when derived from biomass. In this project a series of new furan-like, electron beam curable epoxies were developed and evaluated. Dynamic mechanical analysis, short-beam shear and fracture toughness testing were conducted on un-toughened and toughened, electron beam cured resin systems as a function of dose rate, toughener concentration and post cure temperature.