Macrocomposites made by injection molding

Abstract Macrocomposites can be prepared by injection molding an engineering resin into a mold which contains an insert of a different engineering resin. Using 3/8‐inch beams and 1/4‐inch disks as model systems, we have shown that macrocomposites give parts with combinations of stiffness and toughness far superior than can be made by conventional injection molding of a single material. The key to making macrocomposites with good properties is to have the insert sufficiently hot so that the surface is melted during the second molding step. The toughness of a macrocomposite can be derived not only from proper positioning of a tough material and a stiff material, but also from more effective orientation of glass fibers resulting from the alteration of the mold cavity caused by the insert. Before macrocomposites can be commercialized, significant technical obstacles with respect to both molding equipment and part design procedures must be overcome.