40% Graphite Thermoset PI (ASTM D6456 Type II Class 2)
ASTM D6456 type II class 2 is a grade of thermoset PI. It has the lowest ductility compared to the other variants of thermoset PI. The graph bars on the material properties cards below compare ASTM D6456 type II class 2 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
120 MPa 17 x 103 psi
Elongation at Break
2.0 %
Flexural Modulus
4.8 GPa 0.7 x 106 psi
Flexural Strength
68 MPa 9.9 x 103 psi
Tensile Strength: Ultimate (UTS)
46 MPa 6.7 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
1.7 W/m-K 1.0 BTU/h-ft-°F
Thermal Expansion
38 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 Resistivity Order of Magnitude
15 10x Ω-m
Otherwise Unclassified Properties
Density
1.6 g/cm3 100 lb/ft3
Limiting Oxygen Index (LOI)
40 %
Water Absorption After 24 Hours
0.14 %
Water Absorption At Saturation
3.6 %
Common Calculations
Strength to Weight: Axial
8.0 points
Strength to Weight: Bending
18 points
Thermal Diffusivity
0.95 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
Reinforced Plastics Durability, Geoffrey Pritchard (editor), 1999
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