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Investigation of microstructural changes in impacted polyurea coatings using small angle X-ray scattering (SAXS)

Published online by Cambridge University Press:  05 March 2012

Edward Balizer
Affiliation:
Naval Surface Warfare Center, Carderock Division, Bethesda, Maryland 20817
Jeffry Fedderly
Affiliation:
Naval Surface Warfare Center, Carderock Division, Bethesda, Maryland 20817
Gilbert Lee
Affiliation:
Naval Surface Warfare Center, Carderock Division, Bethesda, Maryland 20817
Susan Bartyczak
Affiliation:
Naval Surface Warfare Center, Dahlgren Division, Dahlgren, Virginia 22448
Willis Mock Jr.
Affiliation:
Naval Surface Warfare Center, Dahlgren Division, Dahlgren, Virginia 22448

Abstract

Three polyureas with decreasing soft segment molecular weights of 1000, 650, and a 250/1000 blend were molded onto circular steel plates and then impacted with a high speed (275 m/s) conical-shaped steel cylinder. The polyurea layer of the post mortem bilayers was characterized on a molecular level by small angle synchrotron X-ray scattering (SAXS) at the Advanced Photon Source at the Argonne National Laboratory. Analysis revealed that the hard domains of the polyureas with lower molecular weight soft segments reformed and oriented over a greater area of the coating, thus increasing the polymer strain hardening and resulting in visibly less out of plane bilayer deformation. This agrees with the hypothesis that polymer strain hardening is a mechanism that retards necking failure of the metal plate.

Type
Technical Articles
Copyright
Copyright © Cambridge University Press 2011

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