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Full Record for Micrograph 559

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- Micrograph no
- 559
- Brief description
- Shear bands in stressed polycarbonate
- Keywords
- craze
, polycarbonate (PC), polymer
, shear bands
- 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
- To promote the formation of shear bands in polycarbonate, acetone is used. This results in the otherwise tough material becoming very brittle
- Technique
- Scanning electron microscopy (SEM)
- Length bar
- 800 μm
- Further information
- Yielding in glassy polymers often proceeds by a small sheared region propagating through the material. These patterns can be used in the stress analysis of fracture processes. In addition, 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.
- 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