Izod impact tests of polypropylenes: The clamping pressure influence

In this work, an experimental program was performed to determine the influence of clamping pressure on the Izod pendulum impact resistance of several polypropylene homopolymers provided by Repsol-YPF Co. Several sets of tests performed indicate how the uncontrolled application of a clamping pressure may lead to non-consistent results. One of the most influential parameters on the clamping torque sensitivity is temperature. From the results obtained, the following conclusion can be established: the clamping pressure is an influential factor only over the material Tg and its effect is related to the material brittleness, diminishing as the temperature comes closer to the brittle-ductile transition temperature.