The development of an instrumented projectile impact test: Data glass‐reinforced and impact‐modified polypropylene

Abstract Characteristics of several impact test methods in current use are discussed. The construction, operation and performance of an instrumented plate‐projectile (IFF) impact tester is described. Force‐strain curves, energies to any point in the test and failure modes may be inferred from the test data. Also, by inspection of the tested plate, one can see if there are cracks, blanching (development of microvoids) or ductile deformation. This inspection distinguishes between local and catastrophic failure—an important distinction in selection of materials for specific uses. There is reasonable correlation between values from notched Izod and IPP tests, with the latter somewhat more sensitive. Data illustrate the distinction between good and poor fiber‐to‐matrix coupling in reinforced polypropylene. Although there is some sacrifice of impact strength with improved fiber‐matrix coupling, this is more than counteracted by the improvement in static strength and creep resistance. The data show that coupled glass‐reinforced impact grade polypropylene exhibits an interesting balance of static to impact properties.