Epoxy
Epoxy is a thermoset plastic. It has a moderately low density among the thermoset plastics in the database. The graph bars on the material properties cards below compare epoxy 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
2.4 GPa 0.35 x 106 psi
Elongation at Break
4.5 %
Poisson's Ratio
0.4
Shear Modulus
0.85 GPa 0.12 x 106 psi
Tensile Strength: Ultimate (UTS)
67 MPa 9.7 x 103 psi
Thermal Properties
Glass Transition Temperature
120 °C 250 °F
Maximum Temperature: Autoignition
430 °C 800 °F
Maximum Temperature: Decomposition
430 °C 800 °F
Maximum Temperature: Mechanical
130 °C 270 °F
Specific Heat Capacity
1500 J/kg-K 0.36 BTU/lb-°F
Thermal Conductivity
0.2 W/m-K 0.12 BTU/h-ft-°F
Thermal Expansion
100 µm/m-K
Electrical Properties
Dielectric Strength (Breakdown Potential)
16 kV/mm 0.63 V/mil
Electrical Resistivity Order of Magnitude
13 10x Ω-m
Otherwise Unclassified Properties
Density
1.3 g/cm3 81 lb/ft3
Limiting Oxygen Index (LOI)
20 %
Refractive Index
1.6
Common Calculations
Stiffness to Weight: Axial
1.0 points
Stiffness to Weight: Bending
34 points
Strength to Weight: Axial
14 points
Strength to Weight: Bending
28 points
Thermal Diffusivity
0.1 mm2/s
Thermal Shock Resistance
20 points
Followup Questions
Further Reading
Epoxy Polymers: New Materials and Innovations, Jean-Pierre Pascault and Roberto J. J. Williams (editors), 2010
ASTM C904: Standard Terminology Relating to Chemical-Resistant Nonmetallic Materials
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