Thermosetting plastic
Thermosetting plastics are plastics that are softened and moulded under heat and cannot then be reshaped.When a thermosetting plastic is softened and moulded, the chain stuctures in the substance react with each other and form cross-links. This causes a huge, three-dimensional, structure to be built up. This is why thermosetting plastics can only be formed once. Thermosetting plastics are mostly used as heat insulators because of their high resistance to heat. They do not soften under heat which is used to good effect as a functional property.
List of some thermosetting plastics:
- Bakelite (used in electrical insulators and plastic wear)
- Urea-Formaldehyde (used in electrical fittings)
- Melamine (used on worktop surfaces)
- Polyester Resin (used in glass-re-inforced plastics)
- Epoxy Resin (used as an adhesive and in Glass Reiforced plastic/Fibreglass)
List of methods used to mould thermosetting plastics:
- Injection Moulding (used for objects like milk bottle crates)
- Extrusion Moulding (used for making pipes, threads of fabric and insulation for electrical cables)
- Calendering (used for making large sheets of plastic)
- Compression Moulding (used to shape most thermosetting plastics)
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