Molding of Oriented Short Fiber Composites. III. Rate Effects on Fiber Alignment in Convergent Channels

In an extension of the experiments performed on the compacted flow of a glass fiber- filled epoxy resin through a conical converging channel under a high pressure, this study examines the orientability of the fibers as the suspension flows into an expty mold cavity. The tensile properties of molded rods of 1/46 to 1/26 diameter reflect the level of orientation produced. Both the fiber orientability and the resulting orien- tation distribution depend strongly on the rate of elongation. The molded-in orientation distribution is also determined by the extent of convergence. Convergence angle, viscosity, and fiber length are secondary variables. The results indicate that fibers can be oriented to within 20 of the flow axis by this technique in order to maximize mechanical performance. The anomalous dependence on the rate of elongation is thought to result from the high voidate in the material during flow.
See also report dated 5 Apr 1974, AD776591.