Unfilled Thermoset PI (ASTM D6456 Type I)
ASTM D6456 type I is a grade of thermoset PI. It has the highest strength and highest ductility compared to the other variants of thermoset PI. The graph bars on the material properties cards below compare ASTM D6456 type I 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
Compressive (Crushing) Strength
210 MPa 31 x 103 psi
Elongation at Break
5.9 %
Flexural Modulus
3.1 GPa 0.45 x 106 psi
Flexural Strength
100 MPa 14 x 103 psi
Impact Strength: Notched Izod
43 J/m 0.8 ft-lb/in
Poisson's Ratio
0.4
Tensile Strength: Ultimate (UTS)
81 MPa 12 x 103 psi
Thermal Properties
Glass Transition Temperature
360 °C 680 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
370 °C 700 °F
Maximum Temperature: Autoignition
380 °C 720 °F
Maximum Temperature: Decomposition
330 °C 630 °F
Maximum Temperature: Mechanical
260 °C 500 °F
Specific Heat Capacity
1130 J/kg-K 0.27 BTU/lb-°F
Thermal Conductivity
0.29 W/m-K 0.17 BTU/h-ft-°F
Thermal Expansion
54 µm/m-K
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 MHz
3.1
Dielectric Strength (Breakdown Potential)
20 kV/mm 0.78 V/mil
Electrical Dissipation At 1 MHz
0.0034
Electrical Resistivity Order of Magnitude
15 10x Ω-m
Otherwise Unclassified Properties
Density
1.4 g/cm3 87 lb/ft3
Limiting Oxygen Index (LOI)
40 %
Water Absorption After 24 Hours
0.24 %
Water Absorption At Saturation
3.6 %
Common Calculations
Strength to Weight: Axial
16 points
Strength to Weight: Bending
30 points
Thermal Diffusivity
0.18 mm2/s
Followup Questions
Further Reading
ASTM D6456: Standard Specification for Finished Parts Made from Polyimide Resin
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
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015