Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Full Record for Micrograph 585

Full Record for Micrograph 585

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Micrograph no
585
Brief description
Internal surface of blow-moulded HDPE
Keywords
blow moulding Link to MATTER Glossary entry for blow moulding, bottle, catspaws, HDPE, parison Link to MATTER Glossary entry for parison, polyethylene (PE), polymer Link to MATTER Glossary entry for polymer, surface
Categories
Polymer
System
High density polyethylene (HDPE)
Composition
Not specified
Standard codes
Reaction
Processing
A 'parison' (tube) is continuously extruded into a mould which periodically closes together with a knife, to cut suitable lengths which are then expanded to fill the mould
Applications
Blow moulding is a continuous process used in the manufacture of bottles as well as sheets, bags, and tubes.
Sample preparation
The specimen has been sputter-coated with gold, to give a conducting surface
Technique
Scanning electron microscopy (SEM)
Length bar
6 μm
Further information
The surface shows ~5 micron periodic ridges which are indicative of flow instability and a periodic slipping of the melt at the die wall. On a finer scale are catspaws of submicron polymer, drawn up by the 'wind' in the blowing process.
Contributor
J A Curran
Organisation
Department of Materials Science and Metallurgy, University of Cambridge
Date
03/10/02
Licence for re-use
Attribution-NonCommercial-ShareAlike 4.0 International
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