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10% PTFE and 15% Graphite Thermoset PI (ASTM D6456 Type II Class 3)

ASTM D6456 type II class 3 is a grade of thermoset PI. It has the second lowest strength compared to the other variants of thermoset PI. The graph bars on the material properties cards below compare ASTM D6456 type II class 3 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

3.1 %

Flexural Modulus

3.1 GPa 0.45 x 106 psi

Flexural Strength

60 MPa 8.7 x 103 psi

Tensile Strength: Ultimate (UTS)

42 MPa 6.0 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

0.76 W/m-K 0.44 BTU/h-ft-°F

Thermal Expansion

54 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz


Dielectric Strength (Breakdown Potential)

20 kV/mm 0.78 V/mil

Electrical Resistivity Order of Magnitude

15 10x Ω-m

Otherwise Unclassified Properties


1.5 g/cm3 95 lb/ft3

Limiting Oxygen Index (LOI)

40 %

Water Absorption After 24 Hours

0.21 %

Water Absorption At Saturation

3.6 %

Common Calculations

Strength to Weight: Axial

7.6 points

Strength to Weight: Bending

18 points

Thermal Diffusivity

0.44 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