B-Staged Epoxy/Single-Walled Carbon Nanotube Nanocomposite Thin Films for Composite Reinforcement Graham L. Warren, 1 Luyi Sun, 1 Viktor G. Hadjiev, 2 Daniel Davis, 3 Dimitris Lagoudas, 3 Hung-Jue Sue 1 1 Polymer Technology Center, Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843-3123 2 Texas Center for Superconductivity and Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-5002 3 Department of Aerospace Engineering, Texas A&M University, College Station, Texas 77843-3141 Received 12 March 2008; accepted 23 May 2008 DOI 10.1002/app.29375 Published online 29 December 2008 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: B-staged epoxy/single-walled carbon nan- otube (SWCNT) nanocomposite thin films at 50% cure were prepared to improve the conductivity and mechani- cal performance of laminated composites. The SWCNTs were functionalized by oxidation and subsequent grafting with polyamidoamine generation-zero dendrimers. The epoxy nanocomposites containing SWCNTs were success- fully cast into thin films by the manipulation of the degree of cure and the viscosity of the epoxy. Raman mi- croscopy characterization revealed that the thin films exhibited a high degree of SWCNT dispersion in the ep- oxy. The B-staged thin films were seamlessly integrated into laminated composite systems upon heating and could serve as interleaves to improve the conductivity and mechanical strength of laminated fiber composite systems. V V C 2008 Wiley Periodicals, Inc. J Appl Polym Sci 112: 290–298, 2009 Key words: dispersions; films; mechanical properties; Raman spectroscopy; resins INTRODUCTION Since their discovery, 1 carbon nanotubes, especially single-walled carbon nanotubes (SWCNTs), have attracted significant interest because of their remark- able properties. 2–5 Among a wide range of applica- tions, SWCNTs have been considered as ideal reinforcing agents for composite applications 6 because of their superior Young’s modulus ( 1 TPa) 7 and high aspect ratio 8 values. In addition to their extremely high modulus and strength values, SWCNTs possess a high electrical conductivity (>10 4 S/cm) 9 and thermal conductivity (>2000 W m 1 K 1 ), 10 which enable the preparation of multi- functional high-performance polymer composites. In recent years, SWCNT-based polymer nanocompo- sites have been extensively studied through the use of a wide range of polymer matrices, 11–13 which have included epoxy, 14–16 polypropylene, 17 polyethy- lene, 18 poly(methyl methacrylate), 19 polyacryloni- trile, 20 and poly(vinyl alcohol), 21 for various structural and functional applications. To fully impart the unique properties of SWCNTs into polymers, it is critical to achieve (1) good dis- persion of the SWCNTs in the polymer matrices, (2) strong adhesion between the SWCNTs and the ma- trix, and (3) alignment of the SWCNTs. 11,12 Vast research efforts have been made to address these needs, among which the surface functionalization of SWCNTs is an attractive approach because it can address both the dispersion and adhesion attributes. Both covalent and noncovalent functionalization methods have been extensively studied and devel- oped over the years. 13 Each method has its own advantages and disadvantages. In most polymer/SWCNT nanocomposites, it is de- sirable to prepare uniformly dispersed SWCNTs in a polymeric matrix to achieve an overall high material performance and multifunctionality. However, a high concentration of SWCNTs in the matrix would usu- ally be needed to do so. This, in turn, would lead to a significant increase in cost and a compromise in proc- essability, especially for the fabrication of laminated composites by vacuum-assisted resin transfer mold- ing (VARTM). Alternative approaches have to be undertaken to strategically place SWCNTs in loca- tions of interest within the composite system. Journal of Applied Polymer Science, Vol. 112, 290–298 (2009) V V C 2008 Wiley Periodicals, Inc. Correspondence to: H.-J. Sue (hjsue@tamu.edu). Contract grant sponsor: U.S. Air Force AFRL; contract grant number: FA8650-05-D-1912 (Minority Leaders Pro- gram). Contract grant sponsor: State of Texas through the Texas Center for Superconductivity, University of Houston (partial support to V.G.H.).