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Full Record for Micrograph 595

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Micrograph no
595
Brief description
Thermoset case of an electrical plug
Keywords
electrical, formaldehyde, injection moulding Link to MATTER Glossary entry for injection moulding, network, plug, polymer Link to MATTER Glossary entry for polymer, thermoset, urea, urea formaldehyde
Categories
Polymer
System
Urea formaldehyde
Composition
Not specified
Standard codes
Reaction
Processing
Reaction injection moulding
Applications
Thermosets are cross-linked networks; hard but unprocessable after the initial reaction. They are used as adhesives, composite matrices, and to make casings for electrical equipment.
Sample preparation
A cross-section has been cold-mounted and stained with dye to highlight the filler material
Technique
Reflected light microscopy
Length bar
100 μm
Further information
The microstructure revealed by the dye consists of seams of filler material (flour or wood-pulp) which is introduced to the melt in a 2:1 ratio part way through the moulding process. Urea thermosets are used because they are hard, inexpensive, and have good resistance to electrical arcing. An additional benefit of a thermoset as opposed to a thermoplastic in this application is that should a failure occur, it will fail in a safe mode (charring, but retaining it form, rather than melting).
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