ABSTRACT
One-dimensional processes include coatings and adhesives. In the application of coatings and adhesives the most important dimension is usually the thickness of the coating. The first step in solvent casting is the preparation of the substrate. The substrate surface, which may be metal or polymer, may be cleaned with a surfactant solution or degreased with liquid Tetrahydrofuran, acetone, or vapor phase isopropanol. The two-dimensional fabrication processes include extrusion, the production of fibers, and lamination. The rapidity with which the isocyanate-polyol reaction takes place in the synthesis of polyurethanes has been used to advantage in reaction injection molding. Polyurethane foams can be categorized as soft, rigid or semirigid and are crosslinked in structure. Surfactants are required in foam production in order to control the bubble size, which is achieved through control of surface energy. One method of overcoming this problem is to fabricate a porous polyurethane tubing.
