| A new type of environmental-friendly polyurethane(PU) waterproofing coating was prepared, whose solidifing agent is water. At the same time, the PU waterproofing coating was modified with OMMT and nano-silica. This paper discusses the influence of the content of water and other primary material to the mechanical properties of the coating, and analyses the relation between structure and properties of nanocomposites by SEM, XRD, AFM, FTIR, TEM, especially the influence of nano-particle to the structure and properties after ultraviolet aging and thermal oxidization.As the solidifing agent of PU waterproofing coating, the content of water influence the solidifying speed and the mechanical properties. If the content of water is deficient, the solidifying speed is low and the mechanical properties are inferior; On the contrary, the mechanical properties also decrease because the coating shrinks and froth. So the content of water is 6-8% at best. This paper also analyses the influence of the proportion of the -NCO , Poly(propylene glycol) and AB two component to the mechanical properties. Comparing the influence of water and MOCA as solidified agent, the mechanical properties with water is less than that of MOCA, but the bond strength of humid area is 46% better than that of MOCA. So the PU coating with water as solidified agent is applicable to the humid area.The PU/OMMT waterproofing coating was prepared by intercalative polymerization. The mechanical properties of PU/OMMT is superior to that of PU waterproofing coating. Especially OMMT layer could shield the ultraviolet radiation and heat. The PU/OMMT waterproofing coating has better resistance to ultraviolet ageing and thermal oxidization ageing.The PU waterproofing coating modified by nano-silica which was grafted with TDI was prepared. The analysis of mechanical properties indicates nano- SiO2 could both improve the mechanical properties and the resistance to ultraviolet ageing and thermal oxidization ageing.
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