PTFE Resin Powder: Tetrafluoroethylene Polymerised under Pressure, Plunkett 1941

PTFE (polytetrafluoroethylene) is the chemically inert plastic. Roy Plunkett found that tetrafluoroethylene, kept under pressure at room temperature, slowly turns into a white solid (US 2,230,654, 1941). A little silver nitrate speeds it up: 7 parts of the gas with 0.1 part silver nitrate at 25 °C for 21 days gave 2.3 parts of polymer. The powder dissolves in nothing usual, does not burn on its own, and melts only at red heat. The picture: our diagram.

متقدم

3 weeks

التعليمات

Charge the cylinder

Put 0.1 part of silver nitrate in a steel pressure cylinder, close it and condense in 7 parts of tetrafluoroethylene, so it stands under its own pressure.

المواد لهذه الخطوة:

رباعي فلورو الإيثيلين7 parts

الأدوات المطلوبة:

نترات الفضة

أسطوانة غاز مضغوط

مصيدة باردة

ميزان ذو كفّتين

نظارة واقية من رذاذ الكيماويات

قفازات مطاطية

Leave at 25 °C for 21 days

Keep the cylinder at 25 °C for 21 days. Warmer is faster. Without the silver nitrate, 10 days gave only about 7 %.

الأدوات المطلوبة:

أسطوانة غاز مضغوط

Remove the gas, take out the powder

Let out the unpolymerised tetrafluoroethylene (ours: into a cold trap to use again) and take out the solid polymer: about 2.3 parts, a third of the gas.

الأدوات المطلوبة:

مصيدة باردة