Abstract
Instrumented puncture tests according to ISO 6603-2 and ASTMD3763 were executed for five different Polypropylene compounds (talcum-, glass fibre- and elastomer modified) with specimen thicknesses ranging from 1mm to 4 mm. Over 1500 puncture tests were executed at the Impact & Long-term Behaviour laboratory of the company Borealisr in Linz. This serves as strong foundation for statistical evaluations of the ductile/brittle transition temperature. For different materials and ductile/brittle transition determination methods, similar trends have been observed, which were characterized by introducing shift factors.
Highlights
The energy absorption capacity strongly depends on the morphology of the plastic and the experimental environment
Instrumented puncture tests according to ISO 6603-2 and ASTM D3763 were executed for five different Polypropylene compounds with specimen thicknesses ranging from 1 mm to 4 mm
For different materials and ductile/brittle transition determination methods, similar trends have been observed, which were characterized by introducing shift factors
Summary
The energy absorption capacity strongly depends on the morphology of the plastic and the experimental environment. In the case of impact or puncture tests, temperature and strain rate variations have a significant influence on the failure behaviour: Almost all unoriented plastics exhibit brittle behaviour at low temperatures as well as at high strain rates [1]. Mechanical measurements of different puncture test standards result in distinct force-deflection curves, which in turn give different transitions from ductile to brittle. There is no concise method for the calculation of an exact transition temperature. It is assumed to be somewhere in the transition regime, a temperature range where sudden drops in energy absorption capacity indicate a change of impact behaviour from ductile to brittle. The difference of the transition as a function of specimen thickness, temperature, test standard and other parameters can be determined
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