Masters Theses

Abstract

“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.

Advisor(s)

Forciniti, Daniel

Committee Member(s)

Reed, X. B., Jr.
Fitch, Mark W.

Department(s)

Chemical and Biochemical Engineering

Degree Name

M.S. in Chemical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Fall 2000

Pagination

viii, 56 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2000 Christopher Robert Newman, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Thesis Number

T 7838

Print OCLC #

45902059

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