PEEK: Polyetheretherketone

General Properties

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PEEK

Polyetheretherketone

Polyetheretherketone (PEEK) is a very popular high-performance plastic and belongs to the group of polaryletherketones.

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	145 to 155°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 Temperature	335 to 345°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	130 J/g
Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. Decomposition Temperature	600 to 620°C
Young's Modulus	3700 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	50 to 70 *10^-6/K
Specific Heat Capacity	-
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	1.32 (semi-cr), 1.27 (am) g/cm³
Morphology	Usually semi-crystalline thermoplastics, but as a thin film generally amorphous
General properties	Good mechanical properties. High stability and stiffness. High temperature resistance. Good chemical and radiation resistance. Good hydrolysis resistance. Good sliding properties. Good electrical insulation properties
Processing	Injection molding, extrusion, machining
Applications	Instrument and apparatus engineering (plain bearings, gear wheels). Aerospace. Electronics. Medical engineering (surgical devices, implants). Chemical industry

NETZSCH Measurement

Instrument	DSC 204 `F1` `Phoenix^®`
Sample Mass	10.39 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phase	3 min / 3 min / 5 min
Heating/Colling Rates	10 K/min
Crucible	Al, pierced lid
Atmosphere	N₂ (40 ml/min)

Evaluation

The peak 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 of the PEEK sample of approx. 342°C was essentially the same in both heatings (1^st heating, blue and 2^nd heating, red). The melting transition in the 2^nd heating was more complex than in the 1^st heating. The melting enthalpy increased from 41 J/g in the 1^st heating to approx. 57 J/g in the 2^nd heating, an increase of almost 40%. The 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, which characterizes the amorphous part, was 151°C (midpoint) in the 2^nd heating (red).