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Applicability of Modern Analytical Techniques to Detection of Changes in Roofing Membrane Materials Brought About By Heat Aging.


pdf icon Applicability of Modern Analytical Techniques to Detection of Changes in Roofing Membrane Materials Brought About By Heat Aging. (618 K)
Rossiter, W. J., Jr.; Byrd, W. E.; Roberts, W. E.; Bailey, D. M.

International Waterproofing Association. International Congress, 9th. April 26-28, 1995, Amsterdam, Netherlands, International Waterproofing Association, 244-242 pp, 1995.

Keywords:

building technology; roofs; heat; aging; membranes

Abstract:

The U.S. Army Construction Engineering Research (CERL) has been investigating the development of a test methodology for evaluating the service life of roofing membrane materials. As part of this effort, CERL conducted a study to investigate the applicability of strain energy (a mechanical test) and Fourier transform infrared (FTIR) spectroscopy (a chemical analysis) as methods for characterizing changes that roofing membrane materials may undergo upon exposure to elevated temperatures. In the case of FTIR, the intent was to evaluate whether changes in the carbonyl index as a function of thermal exposure could be used as an indicator of the stability of the membrane materials. The carbonyl index is the ratio of the intensity of the carbonyl absorption band (i.e., C=O) to that of another band (such as C-H stretching or bending) in the spectrum. Increases in a material's carbonyl index after exposure may be an indication that oxidation occurred during the exposure. Measurements of both strain energy and carbonyl index have been used for specific types of membrane materials. Neither has been applied universally to the variety of membrane materials currently available.