Synthesis and Characterization of the Physical, Chemical and Mechanical Properties of Isocyanate-crosslinked Vanadia Aerogels
A strong lightweight material (X-VOx) was formulated by nanocasting a conformal 4 nm thin layer of an isocyanate-derived polymer on the entangled worm-like skeletal framework of typical vanadia aerogels. The mechanical properties were characterized under both quasi-static loading conditions (dynamic mechanical analysis, compression and flexural bending testing) as well as high strain rate loading conditions using a split Hopkinson pressure bar (SHPB). The effects of mass density, moisture concentration and low temperature on the mechanical properties were determined and evaluated. Digital image correlation was used to measure the surface strains through analysis of images acquired by ultra-high speed photography, indicating nearly uniform compression at all stages of deformation during compression. The energy absorption of X-VOx was plotted as a function of the density, strain rate and temperature, and compared with that of plastic foams. X-VOx remains ductile even at −180 °C, a characteristic not found in most materials. This unusual ductility is derived from interlocking and sintering-like fusion of nanoworms during compression. X-VOx emerges as an ideal material for force protection under impact.
H. Luo and J. Schnobrich and S. Mulik and Y. Zhang and B. P. Grady and A. Capecelatro and L. Sotiriou-Leventis and H. Lu and N. Leventis and G. Churu and A. Dass and E. F. Fabrizio and A. Hobbs, "Synthesis and Characterization of the Physical, Chemical and Mechanical Properties of Isocyanate-crosslinked Vanadia Aerogels," Journal of Sol-Gel Science and Technology, Springer Verlag, Nov 2008.
The definitive version is available at http://dx.doi.org/10.1007/s10971-008-1788-y
United States. Air Force. Office of Scientific Research
NASA Glenn Research Center
National Science Foundation (U.S.)
University of Missouri Research Board
Article - Journal
© 2008 Springer Verlag, All rights reserved.