Flaking and degradation of polyurethane coatings after 2 years of outdoor exposure in Lhasa  

作　　者：LIU FuChun HAO YongSheng WANG ZhenYu SHI HongWei HAN EnHou KE Wei 

机构地区：[1]State Key Laboratory for Corrosion and Proteetion, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China

出　　处：《Chinese Science Bulletin》2010年第7期650-655,共6页

基　　金：supported by the National Natural Science Foundation of China(Grant No.50499334);the National Key Technology R&D Program of China(Grant Nos.2007BAB27B02-02,2009BAE0B02)

摘　　要：The exposure of a high gloss polyurethane aircraft topcoat system with polyurethane intermediate coating and epoxy primer to strong ultraviolet radiation in Lhasa,Tibet was studied by using scanning electron microscopy(SEM) ,atomic force microscopy(AFM) ,attenuated total reflectance Fourier-transform infrared(ATR-FTIR) ,and X-ray photoelectron spectroscopy(XPS) .Micro-flakes were found to form on the topcoat surface after exposure and the size and quantity of the flakes increased with the increase of the exposure time.The magnitude of micro-bulges and the topcoat roughness increased after a long exposure to sunlight. Flakes and micro-bulges resulted in the loss of the topcoat gloss.ATR-FTIR and XPS analysis indicated that chain scissions of the polyurea C==O group and the polyurethane C―O―C and CO―NH groups occurred,and the degradation products of NH and carbonyl groups formed due to the exposure.The breaking of the chemical structure of the polyurethane resulted in a decrease in its elasticity and in the adhesion of the flakes to its surface.The exposure of a high gloss polyurethane aircraft topcoat system with polyurethane intermediate coating and epoxy primer to strong ultraviolet radiation in Lhasa, Tibet was studied by using scanning electron microscopy （SEM）, atomic force microscopy （AFM）, attenuated total reflectance Fourier-transform infrared （ATR-FTIR）, and X-ray photoelectron spectroscopy （XPS）. Micro-flakes were found to form on the topcoat surface after exposure and the size and quantity of the flakes increased with the in- crease of the exposure time. The magnitude of micro-bulges and the topcoat roughness increased after a long exposure to sunlight. Flakes and micro-bulges resulted in the loss of the topcoat gloss. ATR-FTIR and XPS analysis indicated that chain scissions of the polyurea C=O group and the polyurethane C--O--C and CO--NH groups occurred, and the degradation products of NH and carbonyl groups formed due to the exposure. The breaking of the chemical structure of the polyurethane resulted in a decrease in its elasticity and in the adhesion of the flakes to its surface.

关 键 词：聚氨酯涂料 拉萨 X射线光电子能谱 扫描电子显微镜 XPS分析 户外 退化 剥落 

分 类 号：TQ633[化学工程—精细化工] O484.1[理学—固体物理]