Applicability of Artificial Weathering Tests for Performance Evaluation of Elastomeric Sealants

Abstract

A number of sealant samples, Silicone, D1190, D3405 and other designations, were subjected to the standard battery of ASTM tests used in Ohio for acceptance of sealant materials. In addition, non-standard tests such as artificial weathering, cyclic shear/tension, stress relaxation, creep and modulus of elasticity were carried out on samples of the same materials. The results of the investigation revealed that the standard tests are not sufficient by themselves to characterize the long time behavior of the sealants. This paper presents the results of the artificial weathering tests with a brief description of the others. The artificial weathering tests were carried out for 608 hours and the samples were examined by way of color, surface characteristics, movement of sample, flexibility and hardness. Most of the samples passed the standard tests. However, despite the short duration of exposure in the weathering tester, there were significant differences in the ability of different materials to withstand the artificial weathering. In general, the D3405 materials survived the weathering test well, but they did show some scaling after 608 hours. The D1190 materials were uniformly poor, with some flowing off the exposure panel. Silicone gave the best performance, showing very little effect after 608 hours. The authors recommend continued studies to determine an appropriate exposure time so that the weathering test may be added to the standard bank of tests for elastomeric sealants.