Material Properties of Plastics for Solar-Thermal Collector Mounting Systems
Abstract
In this research, three unreinforced and two glass fiber reinforced plastics for the application in mounting systems of solar-thermal collectors were investigated comprehensively. Therefore, morphological, thermomechanical, mechanical and cyclic fracture mechanical tests were performed. Focus was given on the mechanical properties and the fatigue crack growth (FCG) resistance at service relevant temperatures. In the morphological characterization, for the five materials primarily homogenous material distributions were detected. However, the polymer blend ASA/PC showed a limited miscibility. This was confirmed by the separated glass transition temperatures, which were determined by dynamic mechanical analysis. In terms of mechanical properties, significantly higher values for Young’s modulus and strength as well as lower strain-at-break values were obtained for the glass fiber reinforced polymer grades. Increasing temperatures led to decreasing Young’s moduli and strengths as well as to higher strain-at-break values. The unreinforced plastics revealed an inferior FCG resistance. For all materials, temperature increase evoked a declining FCG behavior. The FCG resistance of the reinforced plastics was influenced by the fiber orientation.