Fatigue Characterization of Potable Water Certified PA and PPA Grades for Solar-Thermal Applications
Abstract
A material screening method for potable water certified plastics for solar-thermal applications based on superimposed cyclic mechanical loading was conducted. One aliphatic polyamide and three semi-aromatic polyphtalamide grades with various glass fiber contents were characterized on specimen level. Therefore, an electro-dynamic testing machine equipped with an in-situ testing device was used to obtain the crack growth kinetics at different temperatures (23°C and 80°C) in different media environments (air and H2O) . At 80°C in H2O, specimens revealed a significantly reduced fatigue crack growth resistance compared to tests at the reference conditions of 23°C in air. Comparing all investigated materials at 80°C in water, the polyamide grade and one polyphtalamide grade revealed the best performance. Due to different slopes in their FCG curves, PA-GF30 showed a superior crack growth resistance at low FCG rates.