Award Date

1-1-2003

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Committee Member

Linda S. Sapochak

Second Committee Member

David Hatchett

Number of Pages

80

Abstract

Polyurethane (PU) foam is used as a shock mitigation material in the national stockpile, which degrades over time. A replacement foam, ReCrete was shown to exhibit acceptable mechanical properties after aging, but fractured with impact testing. Previously, processing ReCrete foam at elevated temperature resulted in a decrease of the modulus (stiffness), which was believed to be related to chemical changes during processing. In this thesis, chemical and structural analysis of ReCrete processed at 25°C and 85°C were performed using photoacoustic infrared spectroscopy, IR imaging, and thermal analysis. The change in modulus was related to thermal decomposition of uretoneimine linkages in the diisocyanate starting material by monitoring the change in intensities of diisocyanate, carbodiimide, and uretoneimine bands in the IR spectra. Thermal analysis (DSC and TMA) were consistent with IR finding, where endothermic and exothermic events could be associated with chemical changes in the foam.

Keywords

Aging; Characterization; Foam; Implications; Polyurethane; Structural

Controlled Subject

Organic chemistry; Polymers; Polymerization; Chemistry; Plastics

File Format

pdf

File Size

3399.68 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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