Polymethylpentene - TPX

Polymethylpentene is a linear isotactic polyolefin more properly known as poly 4-methyl pentene-1, which is manufactured by Ziegler-Natta type catalysis. Copolymers are commercially available grades.

Polymethylpentene is transparent, semi-crystalline, and usually colorless (one common grade is slightly yellow), extremely light - for a polyolefin - expensive.

Its density is 0.83g.cm3 which is quite close to the theoretical minimum for thermoplastics]. Its properties are practically similar to those of other polyolefins, compared to which it is more gas permeable and more brittle.

Its melting point (240 °C) is higher than most polyolefins and retains form stability up to temperatures proximal to this, i.e., with increasing temperature it softens more gradually than is normal for thermoplastics.

It has good release characteristics and good high frequency electrical and important ultrasonic/acoustic properties.

Polymer Type



Advantages of  Polymethylpentene include very low density (0.83 g/cm3)., it is transparent and has a reasonably high continuous use temperature (approx. 75 °C (170 °F)).  Polymethylpentene may be autoclaved for sterilisation. It also has good high frequency electrical properties.


Polymethylpentene is a higher cost than other polyolefins. It may be somewhat brittle (though better impact resistance than Acrylic, Polystyrene or SAN).  Higher mould shrinkage than Polystyrene or SAN.  Poor UV resistance.  Higher gas permeability than other polyolefins.


Applications of Polymethylpentene include, medical components - syringes, dishes, measuring flasks. Microwave cookware, coffee filters. Chemical laboratory apparatus, e.g. dishes, test tubes, sight glasses, tubing.

Other applications include medical and laboratory apparatus and electronic components.

Polymethylpentene can be found in medicial equipment like syringes. Image Credit: Shutterstock/Lipskiy

Polymethylpentene can be found in medicial equipment like syringes. Image Credit: Shutterstock/Lipskiy

Typical Properties

Property Value
Density (g/cm3) 0.83
Surface Hardness RL70
Tensile Strength (MPa) 28
Flexural Modulus (GPa) 1.5
Notched Izod (kJ/m) 0.04
Linear Expansion (/°C x 10-5) 12
Elongation at Break (%) 15
Strain at Yield (%) 6
Max. Operating Temp. (°C) 75
Water Absorption (%) 0.01
Oxygen Index (%) 17
Flammability UL94 HB
Volume Resistivity (log ohm.cm) 16
Dielectric Strength (MV/m) 28
Dissipation Factor 1 kHz 0.0002
Dielectric Constant 1 kHz 2.12
HDT @ 0.45 MPa (°C) 100
HDT @ 1.80 MPa (°C) 41
Material. Drying hrs @ (°C) NA
Melting Temp. Range (°C) 260 - 320
Mould Shrinkage (%) 2.5
Mould Temp. Range (°C) 40 - 70

Source : Abstracted from Plascams

For more information on Plascams please visit RAPRA Technology Ltd.

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