An impact toughness test frequently used on [plastics]. It is related to the [Charpy test], and it is frequently performed by people trained in [Materials Science].

The amount of energy necessary for a pendulum to break a rectangular sample with or without a pre-formed notch in it is measured. In the event that the sample contains a pre-formed notch, it should be oriented so that the pendulum strikes the opposite side from that notch. Care must be taken to test the sample at a temperature similar to its expected operating temperature. It will exhibit a radical decrease in impact toughness below its [glass transition] temperature.

Some sample values include

Acrylic ----------- 40-130 J/m
Nylon 6,6 --------- 110 J/m
Polycarbonate ----- 850 J/m
Polystyrene ------- 10-110 J/m
Polyurethane ------ 430-1200 J/m

An IZOD test may be conducted to evaluate the fracture toughness of a new plastic, as a quality control measure in order to ensure that a batch of plastic has not been weakened unintentionally, or to determine the effectiveness of a new processing technique.

ASTM standard test D4812 is an IZOD test with an un-notched sample. ASTM standard test ASTM D256 is an IZOD test with a pre-notched sample.

Izod Test