TPA: Thermoplastic Polyamide Elastomer

General Properties

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TPA

Thermoplastic Polyamide Elastomer


Thermoplastic elastomers on a polyamide basis (TPAs) belong to the copolymers with alternating succession of hard and soft segments. The block of the hard segments show amide bonds, the soft segments ether or ester bonds.

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-70 to 45°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 Temperature145 to 200°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 Enthalpy20 to 65 J/g
Decomposition Temperature400 to 420°C
Young's Modulus20 to 500 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 Expansion120 to 240 *10-6/K
Specific Heat Capacity2.4 to 2.8 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 Conductivity0.2 W/(m*K)
DensityThe mass density is defined as the ratio between mass and volume. Density0.99 to 1.10 g/cm³
MorphologyThermoplastic elastomer, copolymer with hard and soft segments
General propertiesGood resistance to fuels and lubricating greases
ProcessingInjection molding, extrusion, blow molding
ApplicationsAutomotive industry (seals, hoses)

NETZSCH Measurement

InstrumentDSC 204 F1 Phoenix®
Sample Mass11.70 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phase8 min / 3 min / 8 min
Heating/Colling Rates10 K/min
CrucibleAl, pierced lid
AtmosphereN2 (40 ml/min)

Evaluation

In the 1st heating (blue), this example of TPA shows a 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 at -60°C (midpoint) with a step height Δcp of 0.40 J/(g.K). After a broad, but flat ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermal effect with a peak temperature of 32°C (probably a small cold-CrystallizationCrystallization is the physical process of hardening during the formation and growth of crystals. During this process, heat of crystallization is released.crystallization) melting of the hard segments occurred in the temperature range between approx. 80°C and 170°C (with a main peak at 153°C and a preceded shoulder at 121°C). In the 2nd heating (red), an ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermal effect can no longer be seen. Both 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 and the endothermal melting range remained. 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 (midpoint) occurred at -61°C; the melting range with main peak at 150°C is not that strongly structured like in the 1st heating. The heat of fusion has almost decreased by half compared to the 1st heating (just under 20 J/g compared to 36 J/g).