Influence of the amorphous phase molecular mobility on impact and tensile properties of polyamide 6,6

In this work, the relationship between molecular mobility of polyamide 6,6 amorphous phase and mechanical properties is studied. PA66 formulations having different glass transition temperatures ( T g ) obtained by additivation, chemical modification of the polyamide chains, and/or water conditioning at different hygrometry levels, are considered. The main emphasis is put on the impact strength, as measured by instrumented Charpy impact tests over a broad temperature range. It is observed that the brittle‐tough transition temperature T B/T is closely correlated with the T g of the samples rather than to the β secondary relaxation.