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Thermoplastic vs thermosetting polymers; Bakelite, epoxy

Short answer

Thermoplastics soften on heating and can be remoulded; thermosets harden permanently and cannot be reshaped. Bakelite: electrical switches, handles. Epoxy resins: adhesives, coatings, glass-reinforced laminates.

How do thermoplastic polymers differ from thermosetting polymers? Give the applications of Bakelite and Epoxy resins.

Thermoplastic vs thermosetting polymers

PointThermoplasticThermosetting
StructureLinear or slightly branched chainsCross-linked 3-D network
Effect of heatSoftens on heating, hardens on cooling (reversible)Sets permanently on heating; does not soften again
MouldingCan be remoulded and recycledCannot be remoulded
SolubilitySoluble in some organic solventsInsoluble and infusible
Mechanical natureSoft, flexible, less strongHard, rigid, strong, brittle
ExamplesPolyethylene, PVC, nylon, polystyreneBakelite, epoxy resin, melamine–formaldehyde

Applications of Bakelite

Bakelite is hard, rigid, heat resistant, a good electrical insulator, and does not soften on reheating. Uses:

  • Electrical switches, plugs, sockets, switch-boards and insulating parts of computers and appliances.
  • Handles of cookers, pans and irons.
  • Laminates (e.g. phenolic printed circuit boards), brake linings, and adhesive for plywood.
  • Telephone cases, radio cabinets, billiard balls, gears and bearings.

Applications of epoxy resins

  • Strong adhesives (Araldite) for metal, glass and ceramics.
  • Surface coatings, paints and protective linings for tanks and pipes.
  • Electrical insulation and potting of electronic components; glass-epoxy laminates for printed circuit boards.
  • Matrix of fibre-reinforced composites (aircraft, boats, sports goods).
  • Flooring, castings, moulds and tools.

✓ Answer checked by Claude Opus 5.5 (high effort)

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