Polymer degradation due to UV aging and its effect on the strength of polyurethane based leading edge protection coatings

 
The work deals with the UV degradation behavior and its influence on the material elastic properties and the rain erosion strength of polyurethane coating systems for rotor blades. Different UV absorbers and radical scavengers (HALS) were used as UV stabilizers. The samples were exposed to QUV aging and analyzed by color and gloss measurement, IR spectroscopy and selected samples by DMA and tensile test as well as additional rain erosion tests. The work shows that UV aging can be a critical parameter in the rain erosion degradation of polyurethane coatings and that it should be considered in the testing and in the selection of leading edge protection systems for wind turbine blades. Also recommendation for coating material developers on UV absorbers and HALS systems can be given.