TPU: Thermoplastic Urethane Elastomer

General Properties

Short Name:

Name:

TPU

Thermoplastic Urethane Elastomer

Urethane-based thermoplastic elastomers (TPUs) are generated by the polyaddition of polyisocyanate with polyols and so-called chain extenders (lower molecular diols). They are linear block copolymers containing hard and soft segments. In accordance with ISO 18064*, there is a segmentation of the TPU group corresponding to the nature of the hydrocarbon component (aromatic or aliphatic) between the urethane linkage of the hard blocks and corresponding to the chemical bonding (ether, ester, carbonate) within the soft blocks.

*DIN EN ISO 18064, Thermoplastic elastomers – Nomenclature and abbreviated terms.
Due to the diversity of existing structures of this thermoplastic elastomer no specifi c chemical structure is given.

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	-50 to -30°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	135 to 220°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	3 to 15 J/g
Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. Decomposition Temperature	390 to 415°C
Young's Modulus	20 to 400 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	130 to 180 *10^-6/K
Specific Heat Capacity	1.85 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	0.19 W/(m*K)
DensityThe mass density is defined as the ratio between mass and volume. Density	1.10 to 1.25 g/cm³
Morphology	Thermoplastic elastomer, block copolymer with hard and soft segments
General properties	High stability and flexibility. Good oil resistance. Good weather resistance (yellowing without property loss). High resilience
Processing	Injection molding, extrusion, blow molding
Applications	Automotive industry (damping elements, clutch elements). Medical engineering (bypass). Technical rubber articles (band conveyors, tooth belts, seals). Dashboards. Shoe soles

NETZSCH Measurement

Instrument	DSC 204 `F1` `Phoenix^®`
Sample Mass	11.82 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 (40 ml/min)

Evaluation

Presented in the above graphic is the 2^nd heating of a TPU. Along with 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 -32°C (Δc_p 0.42 J/(g.K)), reflecting the thermal behavior of the soft segments, the DSC curve displays a broad endothermal eff ect (peak temperature of the main effect 167°C, heat of fusion approx. 8 J/g) that can be attributed to the melting of hard segments.