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Polymethylpentene (PMP)

PMP is an otherwise-unclassified thermoplastic material. It has the lowest density and a fairly low tensile strength among thermoplastics. The graph bars on the material properties cards below compare PMP to: otherwise unclassified thermoplastics (top), all thermoplastics (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

1.1 GPa 0.16 x 106 psi

Elongation at Break

30 %

Impact Strength: Notched Izod

130 J/m 2.4 ft-lb/in

Tensile Strength: Ultimate (UTS)

24 MPa 3.5 x 103 psi

Thermal Properties

Glass Transition Temperature

30 °C 86 °F

Maximum Temperature: Mechanical

140 °C 280 °F

Melting Onset (Solidus)

230 °C 450 °F

Specific Heat Capacity

1750 J/kg-K 0.42 BTU/lb-°F

Thermal Conductivity

0.17 W/m-K 0.1 BTU/h-ft-°F

Thermal Expansion

120 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 Hz


Dielectric Strength (Breakdown Potential)

28 kV/mm 1.1 V/mil

Electrical Resistivity Order of Magnitude

14 10x Ω-m

Otherwise Unclassified Properties


0.83 g/cm3 52 lb/ft3

Refractive Index


Common Calculations

Stiffness to Weight: Axial

0.74 points

Stiffness to Weight: Bending

41 points

Strength to Weight: Axial

8.0 points

Strength to Weight: Bending

22 points

Thermal Diffusivity

0.12 mm2/s

Thermal Shock Resistance

13 points

Followup Questions

Further Reading

SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000

Modern Plastics Handbook, Charles A. Harper (editor), 1999

Plastics Materials, 7th ed., J. A. Brydson, 1999