There are three elements to the cost of a composite: the matrix, the reinforcement and the cost of the fabrication technology. It is affordable fabrication technology that hinders nanocomposite development. Techniques like lay-up, winding etc., mandated by continuous fibers, are simply too expensive. A truly low cost fabrication method would have to be based on short fibers. Individualized nanotubes, however, form dramatically viscous (and non-Newtonian) suspensions. Considerable experience with these suspensions leads Hyperion to conclude that they will never be economically fabricated into reinforced composite shapes. We propose, therefore, to: 1) assemble robust nanotube preforms of the desired size and shape; 2) infiltrate the preforms with monomer; and 3) polymerize the monomer in situ. In as much as carbon nanotubes are of nearly molecular dimension, the resulting composites will be analogous to an interpenetrating network, one component of which is a rigid rod polymer. In such interpenetrating networks, sometimes called "molecular composites", load is transferred via mechanical entanglement and not by surface interaction, the usual rule-of-mixture equations for the properties of short-fiber reinforced composites do not apply.
