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Polystyrene and PTFE preparation and applications

Short answer

Polystyrene is an addition polymer of styrene, prepared by free-radical polymerization; it is rigid, transparent, cheap, and used for packaging, cups, and insulation. PTFE is the addition polymer of tetrafluoroethylene, prepared under pressure; it is chemically inert, heat-resistant, low-friction, and used for non-stick cookware, gaskets, and wire insulation.

What are polystyrene and PTFE? How can they be prepared? What are the main reasons for their wide range of applications?

Polystyrene (PS) is an addition polymer of styrene (vinylbenzene), C₆H₅CH=CH₂. PTFE (Teflon) is the addition polymer of tetrafluoroethylene, CF₂=CF₂.

Preparation

  • Polystyrene: free-radical polymerisation of styrene with benzoyl peroxide as initiator, in bulk, solution or suspension at about 80–100 °C: n C₆H₅CH=CH₂ → [–CH(C₆H₅)–CH₂–]ₙ
  • PTFE: n CF₂=CF₂ → [–CF₂–CF₂–]ₙ using ammonium persulphate initiator under pressure.

Reasons for wide applications

  • Polystyrene: rigid, transparent, light, cheap, easy to mould, good electrical insulator and moisture resistant. Used for packaging, disposable cups, toys, CD cases, appliance housings, and expanded form (thermocol) for insulation and cushioning.
  • PTFE: extremely inert to chemicals, stable to heat (up to 260 °C), very low friction, non-stick and a superb electrical insulator. Used for non-stick cookware, gaskets, bearings, wire insulation and chemical plant lining.

✓ Answer checked by Claude Opus 5.5 (high effort)

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