# 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 10 ^{6} 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 10 ^{3} 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

2.1

Dielectric Strength (Breakdown Potential)

28 *kV/mm* 1.1 *V/mil*

Electrical Resistivity Order of Magnitude

14 *10 ^{x} Ω-m*

## Otherwise Unclassified Properties

Density

0.83 *g/cm ^{3}* 52

*lb/ft*

^{3}Refractive Index

1.5

## 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 *mm ^{2}/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