FEP: Tetrafluoroethylene/hexafluoropropylene copolymer

General Properties

Short Name:

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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 Temperature	253 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 Temperature	510 to 600°C
Young's Modulus	350 MPa
Coeficiente lineal de expansión térmica (CLTE/CTE)The coefficient of linear thermal expansion (CLTE) describes the length change of a material as a function of the temperature.Coefficient of Linear Thermal Expansion	80 *10^-6/K
Specific Heat Capacity	1.12 J/(g*K)
Thermal Conductivity	0.25 W/(m*K)
Density	2.12 to 2.17 g/cm³
Morphology	Semi-crystalline polymer
General properties	Good chemical resistance. High impact strength. Smooth surface
Processing	Injection molding, extrusion
Applications	Heating 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

Instrument	DSC 204 `F1` `Phoenix^®`
Sample Mass	11.13 mg
Isothermal Phase	5 min
Heating/Colling Rates	10 K/min
Crucible	Al, pierced lid
Atmosphere	N₂ (50 ml/min)

Evaluation

The present FEP sample shows an endothermal melting eff ect at 266°C (peak temperature, 2^nd 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 2^nd heating (266°C compared to 268°C in the 1^st heating, blue) can be explained by a better contact between the sample and crucible bottom after the first melting. The melting peak in the 1^st heating (blue) is a bit slimmer compared to the 2^nd heating; this indicates a narrower distribution of crystallite size.