Two-dimensional mapping of tensile strength for injection molded composites of glass fiber reinforced polypropylene

An array of polypropylene composites were injection molded into rectangular plaques having a single side gate. As a consequence of non-symmetrical flow patterns giving complex distribution of fiber orientations, measured tensile strength values of test specimens cut along X-Y directions produced non-linear and anisotrapic trendlines. Chemical coupling, glass fiber content and the choice of short-long glass fiber reinforcement are shown to be material variables influencing the magnitude of the tensile strength at any given localized position. This data verifies the notion that tensile strength evaluation along just the flow direction is insufficient for anticipating end use performance.