“Before the Montreal Protocol of 1987 and the subsequent phasing-out of chlorofluorocarbons in industrial applications, rigid polymer foams were made using these compounds as secondary blowing agents. The CFCs remain trapped in the gaseous part of the cellular foam structure, and once disposed of these foams constitute a significant reservoir for the environmental release of ozone-depleting chemicals. Environmental degradation of the foam speeds up this process. Of particular interest in this work is the degradative effect of ultraviolet (UV) light on rigid polyurethane foams. Foams were subjected to accelerated weathering conditions and then viewed with a scanning-electron microscope. The thin cell membranes near the foam surface degrade when exposed to UV light, leaving only a network of polymer struts that offers negligible resistance to the escape of CFCs or any other gases contained within. This effect has been reproduced qualitatively through simulated weathering of a computer-generated foam structure. If enough is known about the optical properties and photosensitivity of the polymer foam, this simulation technique can be used to estimate the rate of weathering penetration in any situation where photodegradation is the primary concern”--Abstract, page iv.
Reed, X. B., Jr.
Fitch, Mark W.
Chemical and Biochemical Engineering
M.S. in Chemical Engineering
University of Missouri--Rolla
viii, 56 pages
© 2000 Christopher Robert Newman, All rights reserved.
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Newman, Christopher Robert, "Modeling the ultraviolet photodegradation of rigid polyurethane foams" (2000). Masters Theses. 1985.
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