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Micrograph 570 and full record
- Micrograph no
- 570
- Brief description
- Strain-induced birefringence in a notched polycarbonate bar
- Keywords
- bending, birefringence
, polycarbonate (PC), polymer , stress - Categories
- Polymer
- System
- Polycarbonate (PC)
- Composition
- Not specified
- Standard codes
- Reaction
- Processing
- Applications
- Polycarbonate is a clear and relatively tough plastic used to make shatterproof windows, lenses and even helmets. It is also used to make compact discs.
- Sample preparation
- A notch has been cut in the bar to illustrate stress concentration. A four-point bending rig is used to apply stress.
- Technique
- Cross-polarised light microscopy
- Length bar
- 6 mm
- Further information
- The colours in the image are the result of birefringence and relate to the strain-induced alignment of the polycarbonate molecules. Because the specimen is below the glass transition temperature of PC (145 deg C), the material will relax when the stress is removed and there will be no residual alignment. The colours reveal the pattern of stress concentration around the notch.
- Contributor
- J A Curran
- Organisation
- Department of Materials Science and Metallurgy, University of Cambridge
- Date
- 03/10/02
- Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales- Related micrographs
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