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Full Record for Micrograph 578

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- Micrograph no
- 578
- Brief description
- Sprue in a sample of polypropylene (PP)
- Keywords
- alignment, birefringence
, injection moulding
, polymer
, polypropylene (PP), sprue
- Categories
- Polymer
- System
- Polypropylene (PP)
- Composition
- Not specified
- Standard codes
- Reaction
- Processing
- Polypropylene is injected into a mould via this inlet or 'sprue'
- Applications
- Polypropylene has good resistance to chemicals and to fatigue. It is widely used in food packaging in the form of rigid tubs, lids and screw-tops as well as in flexible films.
- Sample preparation
- Technique
- Cross-polarised light microscopy
- Length bar
- 10 mm
- Further information
- The colours in the image are the result of birefringence and relate to the residual strain in the polypropylene. The pattern of strain is indicative of the flow of material during the injection process and highlighting the injection point or 'sprue' from which all the material flows radially into the mould. The molecules are aligned parallel to the direction of flow.
- 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