AbstractChopped aramid fiber reinforced ionomer formulations were investigated as prototypes of military armor materials effective in providing protection against munition fragments. The dependence of ballistic impact resistance upon fiber openness was demonstrated by radiographs. Concentrations of 30 percent or less by volume of 1/4 and 1/2 in. fibers were injection moldable, However, the greater than optimum dispersion of fibers as a result of extrusion compounding or of the injection molding itself resulted in lower ballistic resistance and in usually lower tensile and flexural strength properties than were achieved by compression molding: Compression molding of suitably opened 1/4, 1/2 and 2 in. fibers produced rigid materials with fiber contents as high as 90 percent by volume. Ballistic impact resistance increased linearly with fiber content.