Mechanical Performance of Polyamides with Influence of Moisture and Temperature – Accurate Evaluation and Better Understanding

The wide use of thermoplastics has put higher demands on designers to conduct more accurate and increasingly sophisticated analysis of materials in order to ensure the performance of the molded parts under the end-use conditions characterized by varying humidity, temperature, and dynamic load or deformation. One of the key aspects in thermoplastic analysis is to apply correct material property parameters obtained using standard testing procedures and under end-use conditions. Previously we reported to SPE (AnTec’97, AnTec’98, and RETEC/ASTM’99) the shortand long-term mechanical properties of polyamides (nylon) with time and temperature effects under dry-as-molded conditions. The current paper focuses on the two of the most influential factors on polyamides’ properties and performance – moisture and temperature. The tensile properties of conditioned polyamides were obtained from – 40°C to 150°C, and the moisture content in the sample was examined immediately after test to ensure that the change in material properties is accurately reflected. The results provided critical understanding on the impact of moisture and temperature on polyamides strength and ductility. The findings in this investigation will enable engineers and product developers to successfully design and evaluate the performance of injection molded nylon parts under end-use conditions.