High performing polyolefin materials for demanding applications like solar absorbers [PEX, PP]

High performing Polyolefins, in terms of mechanical strength and thermal stability, can contribute to an interesting property profile and aid cost reduction in order to aid further growth of renewable energy systems. Cross-linked Polyethylene (PE-X) is discussed in the group of polyethylene, and PP-RCT (Random, Crystalline, Temperature resistance) in the group of polypropylene (PP). Thermal collector systems are currently produced in rather cost intensive manufacturing processes utilising a variety of different, mostly non-plastics materials. There is an extraordinary potential for applying polymeric materials in these collector systems in terms of enhanced functionality with new attractive design and cost reduction. In this paper, polyolefin materials, namely PE-X and PP-RCT, for demanding hot water applications in the field of new energy systems are investigated. For such applications, high temperatures in air and water represent the most challenging service conditions. Hence, the investigation of aging phenomena in such materials at elevated temperatures in water and air is of enormous importance to characterise their performance and to identify possible limitations. The aging behaviour of plastics for solar thermal absorbers using various methods of polymer analysis is presented. Tests like oven ageing, long term hydrostatic pressure testing and circulation loop testing at high temperatures were performed. KEY WORDS : PE-X, PP-RCT, demanding applications, solar absorbers