Evaluating the Durability of Gel Coats Using Outdoor and Accelerated Weathering Techniques: A Correlation Study

摘要

A broad based correlation study has been conducted to evaluate the quality of simulated weather conditions produced by six commonly used accelerated weathering devices. To our knowledge there have been no published correlation studies in which gel coats have been evaluated with the major weathering methods in use. In this study the role of the significant environmental stressors (heat, light, and moisture) will be discussed. The results obtained from acceelrated devices methods have been compared to South Florida (Miami) exposure weathering data. The spectral power distribution (SPD) of the light source in the accelerated weathering device plays a significant role in the acceelrated test agreement with natural testing results. The test temperature directly influences the degree of acceleration of the accelerated test. The agreement of the natural and accelerated methods has been determined by using a Pearson's correlation coefficient matrix. In general the methods with relatively high correlation to South Florida weathering include the Atlas Ci65 xenon arc unit and the EMMAQUA+NTW Fresnel reflector. Poor correlation is noted for the Q Panel QUV weatherometer (313 B bulb). Intermediate correlation values were obtained using the DSET Suntest CPS benchtop xenon arc unit,t he Atlas Sunchine carbon arc unit, and the Q Panel QUV weatherometer (340 A bulb). Acceleration factors were determined for each of the accelerated weathering devices using regreesion analysis. Acceleration factors ranged from 3 to 35 with the more highly correlated devices being 7 to 10 times faster than conventional Miami outdoor weathering.