Giuseppe R. Palmese1, Xing Geng1, John J. La Scala2, and James M. Sands3. (1) Department of Chemical and Biological Engineering, Drexel University, 3141 Chestnut St., CAT 283, Philadelphia, PA 19104, (2) U.S. Army Research Laboratory, AMSRD-ARL--WM-MC, Building 4600, Aberdeen Proving Ground, MD 21005, (3) Army Research Laboratory, Building 4600, Aberdeen Proving Ground, MD 21005
Vinyl Ester (VE) resins are widely used to make polymer matrix composites because of their high modulus, high strength, high glass transition temperature, low weight, and low cost. However, one significant disadvantage of VE resins is low fracture toughness that limits their applications. Traditional methods using butadiene-acrylonitrile copolymer based liquid rubber as a toughener did not achieve satisfactory toughening effect due to its poor miscibility with VE resins as well as its high viscosity. In our study, a novel bio-based rubber (BR) was designed and its toughening effect on VE resins was evaluated. By using VE as a base system, it was demonstrated that significant improvement in fracture toughness (G1c=2000 J/m2 compared to 250 J/m2) is achieved with minimal reduction of Tg. Moreover, the low viscosity associated with the BR toughener provides ease of processing compared to common liquid and particulate rubber modifiers.