Rigid Thermoset Polyurethane (RPU)
RPU is a thermoset plastic. It has the lowest density among thermoset plastics. In addition, it has the highest ductility and the highest heat capacity. The graph bars on the material properties cards below compare RPU to other thermoset plastics (top) 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
2.2 GPa 0.32 x 106 psi
Elongation at Break
90 %
Flexural Modulus
2.0 GPa 0.29 x 106 psi
Flexural Strength
83 MPa 12 x 103 psi
Tensile Strength: Ultimate (UTS)
60 MPa 8.7 x 103 psi
Thermal Properties
Maximum Temperature: Autoignition
380 °C 720 °F
Maximum Temperature: Decomposition
270 °C 520 °F
Specific Heat Capacity
1750 J/kg-K 0.42 BTU/lb-°F
Thermal Conductivity
0.19 W/m-K 0.11 BTU/h-ft-°F
Thermal Expansion
63 µm/m-K
Vicat Softening Temperature
120 °C 240 °F
Other Material Properties
Density
1.2 g/cm3 75 lb/ft3
Dielectric Strength (Breakdown Potential)
19 kV/mm 0.74 V/mil
Electrical Resistivity Order of Magnitude
13 10x Ω-m
Common Calculations
Stiffness to Weight: Axial
1.0 points
Stiffness to Weight: Bending
36 points
Strength to Weight: Axial
14 points
Strength to Weight: Bending
28 points
Thermal Diffusivity
0.090 mm2/s
Thermal Shock Resistance
31 points
Followup Questions
Further Reading
Polyurethanes: Science, Technology, Markets, and Trends, Mark F. Sonnenschein, 2015
Thermosets: Structure, Properties and Applications, Qipeng Guo (editor), 2012
Modern Plastics Handbook, Charles A. Harper (editor), 1999
Plastics Materials, 7th ed., J. A. Brydson, 1999