Volume 34, Issue 2 (March 2006)
Accelerated Aging on Sealants and a Quantificational Way to Evaluate the Durability
Accelerated aging tests, exposure to heat aging (80°C) and UVA ultraviolet radiation (50°C), lasting for 5000 h, were carried out, respectively, on five samples of building sealants in this paper to study their durability. Tensile adhesion data, hardness, and visual observations are reviewed following specific exposure times. The results have shown that UV accelerates the weathering on the sealant's appearance while heat quickens the worse of mechanical properties. The study also shows that curves of the time dependences of mechanical properties can be fitted as polynomial, which present in the status of fluctuation during aging and the extents of fluctuation under different aging conditions are considerably different. As a result, the unreasonable conclusion is easily drawn by calculating aging rate when doing data processing. The method of calculating deviation coefficient proposed by the authors can quantificationally evaluate and compare the durability of tested sealants. From the results of calculated deviation coefficient the sensitive degree of sealants to different aging conditions can be noted as well.