Low temperature slow rate penetration test: Evidence for its sensitivity to the thermomechanical relaxations in the case of ethylene–vinyl acetate copolymers

The sensitivity of a low temperature slow rate penetration test to the dynamic mechanical response of ethylene‐vinyl acetate (EVA) copolymers with different compositions is clearly evidenced. The β‐molecular relaxation process occuring around −10°C controls the slow puncture behavior. The penetration resistance reaches a maximum value at this temperature and the type of rupture involved in the perforation mechanism varies on both sides of this critical temperature (brittle or ductile rupture). The parallel variations of the slow puncture resistance and of the high speed tensile impact strength with temperature, as well as with the vinyl acetate content, point to the reliability of the low temperature slow rate penetration test. This test thus appears as an efficient tool to simulate static mechanical deformations undergone by polymer films used in the sealed packaging of frozen food.