Date of Defense

4-4-1991

Department

Chemistry

First Advisor

George Lowry

Second Advisor

William Kelly

Third Advisor

Phillip Guichelaar

Abstract

Cast polyurethanes are commonly used as thermal barriers for aluminum window frames. The degree of polymerization of the polyurethane affects the properties of the final product. Two urethane systems were studied to determine the effects on the cure caused by variations in the cure time and temperature, and in the initial temperature of the reactants and the mold. It was found that specimens aged under ambient conditions did produce increasingly better results with time; however, the two week values were not equivalent to the control samples. This suggested that bonding and relaxation of internal stresses continued to occur with time. Elevated post cures significantly increased the property performance, allowing a greater degree of crosslinking. Cold temperatures of both the metal and chemical greatly decreased the performance of the polyurethane. The results emphasize the need for critical control of the temperature of both the chemical and metal for the production of more consistent, better performing thermal barriers.

Access Setting

Honors Thesis-Campus Only

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