FEP: Tetrafluoroethylene/hexafluoropropylene copolymer

General Properties

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FEP

Tetrafluoroethylene/hexafluoropropylene copolymer


Fluorinated ethylene propylene (FEP) is similar in its composition to PTFE or PFA; it is, however, softer and can be processed in conventional injection molding.

Structural Formula


Properties

Glass Transition Temperature-
Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).Melting Temperature253 to 282°C
Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).Melting Enthalpy-
Decomposition Temperature510 to 600°C
Young's Modulus350 MPa
Coefficient of Linear Thermal Expansion80 *10-6/K
Specific Heat Capacity1.12 J/(g*K)
Thermal Conductivity0.25 W/(m*K)
Density2.12 to 2.17 g/cm³
MorphologySemi-crystalline polymer
General propertiesGood chemical resistance. High impact strength. Smooth surface
ProcessingInjection molding, extrusion
ApplicationsHeating cables, heating tapes. Electronics (e.g., wires, cables on the communication sector). Chemical industry (lining for valves, tubes, container). Solar cells (layer films)

NETZSCH Measurement

InstrumentDSC 204 F1 Phoenix®
Sample Mass11.13 mg
Isothermal Phase5 min
Heating/Colling Rates10 K/min
CrucibleAl, pierced lid
AtmosphereN2 (50 ml/min)

Evaluation

The present FEP sample shows an endothermal melting eff ect at 266°C (peak temperature, 2nd heating, red) in the temperature range between 0°C and 310°C with a melting enthalpy of 24 J/g. The shift of the peak temperature of more than 2 K to lower values in the 2nd heating (266°C compared to 268°C in the 1st heating, blue) can be explained by a better contact between the sample and crucible bottom after the first melting. The melting peak in the 1st heating (blue) is a bit slimmer compared to the 2nd heating; this indicates a narrower distribution of crystallite size.