# Rigid Thermoplastic Polyurethane (RTPU, PUR-RT)

RTPU is an otherwise-unclassified thermoplastic material. The graph bars on the material properties cards below compare RTPU 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.

## Thermal Properties

Maximum Temperature: Autoignition

270 *°C* 520 *°F*

Maximum Temperature: Decomposition

320 *°C* 600 *°F*

Specific Heat Capacity

1760 *J/kg-K* 0.42 *BTU/lb-°F*

Thermal Conductivity

0.6 *W/m-K* 0.35 *BTU/h-ft-°F*

Thermal Expansion

100 *µm/m-K*

## Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 Hz

3.6

Dielectric Strength (Breakdown Potential)

24 *kV/mm* 0.94 *V/mil*

Electrical Resistivity Order of Magnitude

14 *10 ^{x} Ω-m*

## Other Material Properties

Density

1.1 *g/cm ^{3}* 66

*lb/ft*

^{3}Elastic (Young's, Tensile) Modulus

4.0 *GPa* 0.58 *x 10 ^{6} psi*

Elongation at Break

5.0 *%*

Tensile Strength: Ultimate (UTS)

75 *MPa* 11 *x 10 ^{3} psi*

## Common Calculations

Stiffness to Weight: Axial

2.1 *points*

Stiffness to Weight: Bending

50 *points*

Strength to Weight: Axial

20 *points*

Strength to Weight: Bending

38 *points*

Thermal Diffusivity

0.32 *mm ^{2}/s*

Thermal Shock Resistance

13 *points*

## Followup Questions

## Further Reading

Polyurethanes: Science, Technology, Markets, and Trends, Mark F. Sonnenschein, 2015

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