Micrograph 581 and full record

Micrograph no

581

Brief description

X-ray tomography image of open cell polyurethane foam

Keywords

cell

, composite material

, foam

, polymer

, polymer composite foam, polyurethane (PU), thermoset, X-ray tomography

Categories

Composite, Foam, Polymer, Polymer composite foam

System

Polyurethane (PU)

Composition

Not specified

Standard codes

Reaction

Processing

The principle of x-ray tomography is to re-construct the spatial distribution of the linear attenuation coefficient within the object from X-ray radiographs recorded at different angular settings.

Applications

This open celled polymer foam is a compliant space-filler, used for padding and in furniture. It may also be used as a precursor in processes such as the two-stage casting of a metal foam.

Sample preparation

Technique

X-ray tomography

Length bar

1.5 mm

Further information

If a gas is injected into a liquid it forms a cellular foam structure. When a thermoset prepolymer of low viscosity is foamed, the polymer can drain from the cell walls (driven by surface tension) before it sets at the cell edges, leaving an open-celled foam. The cell edges have three concave sides. The average co-ordination number for the nodes (where struts meet) is four, giving tetrahedral junctions. The deformation behaviour of the foam was observed by X-ray microtomography at the ESRF in Grenoble. X-ray tomography overcomes the limitations of MRI in terms of contrast, and those of confocal optical microscopy in terms of depth of field.

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