Chemical speciation of polyurethane polymers by soft-x-ray spectromicroscopy

Technical Report · Tue Apr 01 04:00:00 EST 1997

DOI:https://doi.org/10.2172/603501· OSTI ID:603501

Rightor, E. G. ^[1]; Hitchcock, A. P.; Urquhart, S. G. ^[2]

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1. Dow Chemical, Freeport, TX (United States)
2. McMaster Univ., Hamilton, Ontario (Canada); and others

Polyurethane polymers are a versatile class of materials which have numerous applications in modern life, from automotive body panels, to insulation, to household furnishings. Phase segregation helps to determine the physical properties of several types of polyurethanes. Polymer scientists believe that understanding the connections between formulation chemistry, the chemical nature of the segregated phases, and the physical properties of the resulting polymer, would greatly advance development of improved polyurethane materials. However, the sub-micron size of segregated features precludes their chemical analysis by existing methods, leaving only indirect means of characterizing these features. For the past several years the authors have been developing near edge X-ray absorption spectromicroscopy to study the chemical nature of individual segregated phases. Part of this work has involved studies of molecular analogues and model polymers, in conjunction with quantum calculations, in order to identify the characteristic near edge spectral transitions of important chemical groups. This spectroscopic base is allowing the authors to study phase segregation in polyurethanes by taking advantage of several unique capabilities of scanning transmission x-ray microscopy (STXM) - high spatial resolution ({approximately} 0.1 {mu}m), high spectral resolution ({approximately}0.1 eV at the C 1s edge), and the ability to record images and spectra with relatively low radiation damage. The beamline 7.0 STXM at ALS is being used to study microtomed sections or cast films of polyurethanes. Based on the pioneering work of Ade, Kirz and collaborators at the NSLS X-1A STXM, it is clear that scanning X-ray transmission microscopy using soft X-rays can provide information about the chemical origin of phase segregation in radiation-sensitive materials on a sub-micron scale. This information is difficult or impossible to obtain by other means.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 603501
• Report Number(s): LBNL--39981; ON: DE97007345; CNN: Grant DMR-9458060
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ABSORPTION SPECTROSCOPY
POLYURETHANES
QUANTITATIVE CHEMICAL ANALYSIS
SOFT X RADIATION
X-RAY SPECTROSCOPY