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 TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.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 reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. Decomposition Temperature	510 to 600°C
Young's Modulus	350 MPa
Coefficient of Linear Thermal Expansion (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 ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.Thermal Conductivity	0.25 W/(m*K)
DensityThe mass density is defined as the ratio between mass and volume. 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
IsothermalTests at controlled and constant temperature are called isothermal.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.