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Thermosetting Plastics

Thermosetting Plastics . Product Design. Thermosetting Plastics . These plastics are formed by chemical reactions which leave them in a relatively fixed state.

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Thermosetting Plastics

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  1. Thermosetting Plastics Product Design

  2. Thermosetting Plastics • These plastics are formed by chemical reactions which leave them in a relatively fixed state. • Thermosetting plastics are formed and ‘set’ in a single operation when a chemical reaction leaves them ‘fixed’ in the shape of the mould. They cannot be softened or reformed when reheated. • Although thermosets can withstand high temperatures, excess heat will simply cause the material to decompose. • An egg yolk is a good analogy for this. When a yolk is raw, it is in a soft liquid state. But if it is heated, it becomes hard and is no longer capable of becoming soft. • Thermosetting plastics are often used when a product needs resistance to extremes in temperature, electrical current, chemicals and wear.

  3. Thermosetting Plastics

  4. Thermosetting Plastics

  5. Epoxy resin (ER) COMMON NAME: Araldite Many adhesives (glues) are thermosetting plastics. A good example is ‘Araldite’ which is an epoxy resin that hardens when a second chemical is added (a catalyst). It will bond most materials including woods and metals as well as some plastics • USES • for bonding of other materials • PROPERTIES • Good electrical insulator • hard • brittle unless reinforced • resists chemicals well

  6. Melamine formaldehyde (MF) COMMON NAME: Formica or Melaware Used in the production of plastic laminates because of its smooth surface and hygienic qualities. PROPERTIES • waterproof • odourless • mark and scratch resistance USES • worktops • buttons • electrical insulation

  7. Urea formaldehyde COMMON NAME: Aerolyte or Cascamite Used in homes as an adhesive resin in pressed wood products • PROPERTIES • good adhesive qualities • stiff, hard and brittle • good electrical insulator • USES • electrical fittings • paper and textile coating • wood adhesive

  8. Polyester resin COMMON NAME: Orel or Beetle PROPERTIES • Stiff, hard and brittle • Resilient as laminated GRP • Formed without heat and pressure USES • panels for car bodies and boat hulls • casting • embedding

  9. GRP One way on reinforcing plastic is to add fibred glass to it. This makes it much stronger and is generally referred to as G.R.P. (glass reinforced plastic). GRP is used in car body repairs, sailing boats, corrugated sheet because of its lightness, toughness and resistance to water.

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