Ablative nanocomposites were prepared by incorporating multiwall carbon nanotubes (MWCNT) into phenolic resin and then impregnating them into rayon-based carbon fabric. MWCNT were blended into phenolic resin at 0.5, 1, and 2 wt% loadings using a combination of sonication and high shear mixing to insure uniform dispersion of MWCNT. The composite test specimens were tested by using an oxyacetylene test bed (OTB) applying a heat flux of 1000？W/cm2 for duration of 45 seconds. Composite specimens with 2？wt% MWCNT showed reduction in mass loss, recession in length, and in situ temperatures compared to control composites. 1. Introduction Ablation is a process of material removal from a surface or other erosive process and usually associated with materials for space reentry vehicles and rocket nozzles. The ablative materials are used as thermal protection materials for rocket nozzles, space vehicles, and combustion chambers of rocket motors. These materials should withstand very high temperatures in the order of thousands of degrees Celsius, high thrust, and high impact. The final material should be able to form complex shapes and be as light as possible. Currently the main consumers of ablative materials are military, NASA, and commercial space launching company. Intensive research on ablative materials began during the space race between the USSR and the USA in 1950s. Some of these research materials were made by universities, while some by private companies, such as Cytec Industries. The most popular material used in the United States, which is the standard material for NASA and other organizations, is MX-4926 manufactured by Cytec Engineered Materials. MX-4926 is a composite material composed of woven rayon-based carbon fiber, carbon black filler, and a phenolic resin matrix. Many research groups, such as Ho et al. [1] and Patton et al. [2], used MX-4926 material as the baseline for the development of polymer nanocomposite ablative materials in their research. Ablative materials have progressed with the introduction of new materials and technologies. Since the late 1990s, nanotechnology has been a new frontier of the scientific community. Nanotechnology deals with particles which have at least one dimension on the nanometer scale [2]. Nanoparticles are materials which are in the purest form that have exceptional fundamental properties. Their high surface-area-to-volume ratio, especially for nanotubes, makes them perfect ablative and reinforcement materials. Addition of proper nanoparticles in polymer matrix can enhance ablative and overall mechanical
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