PEI: Polyetherimide

General Properties

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PEI

Polyetherimide


Polyetherimide (PEI) is a high temperature-resistant high-performance thermoplastic. It is transparent and has a golden yellow color.

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 Temperature215 to 230°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-
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 Temperature540 to 550°C
Young's Modulus2900 to 3000 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 Expansion50 *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 Conductivity0.22 W/(m*K)
DensityThe mass density is defined as the ratio between mass and volume. Density1.27 g/cm³
MorphologyAmorphous
General propertiesHigh stability. High electrical impact strength. Good hydrolysis resistance. High UV and gamma ray resistance. Good resistance to StressStress is defined as a level of force applied on a sample with a well-defined cross section. (Stress = force/area). Samples having a circular or rectangular cross section can be compressed or stretched. Elastic materials like rubber can be stretched up to 5 to 10 times their original length.stress cracking. Self-extinguishing
ProcessingInjection molding, injection blow molding, extrusion, foaming
ApplicationsElectrics/electronics (e.g., housings, circuit boards). Aircraft construction (e.g., panels, coatings). Automobile industry. Medical engineering. Instrument and apparatus engineering

NETZSCH Measurement

InstrumentDSC 204 F1 Phoenix®
Sample Mass11.53 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phase3 min / 3 min / 5 min
Heating/Colling Rates10 K/min
CrucibleAl, pierced lid
AtmosphereN2 (40 ml/min)

Evaluation

Polyetherimide (PEI) is completely amorphous and belongs to the high-temperature plastics, as reflected by the high 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 of approx. 217°C in the 2nd heating (red, midpoint) and 215°C in the 1st heating (blue). 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 in the 2nd heating is overlapped with a small RelaxationWhen a constant strain is applied to a rubber compound, the force necessary to maintain that strain is not constant but decreases with time; this behavior is known as stress relaxation. The process responsible for stress relaxation can be physical or chemical, and under normal conditions, both will occur at the same time. relaxation peak. The controlled cooling at 10 K/min was probably far slower than the cooling rate employed during production of the polymer, causing the short-range order that was responsible for the endothermal RelaxationWhen a constant strain is applied to a rubber compound, the force necessary to maintain that strain is not constant but decreases with time; this behavior is known as stress relaxation. The process responsible for stress relaxation can be physical or chemical, and under normal conditions, both will occur at the same time. relaxation peak.