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Silicone Plastic

Silicone plastic is a thermoset plastic. It has the lowest heat capacity among thermoset plastics. In addition, it has a fairly high density and a fairly high dielectric strength. The graph bars on the material properties cards below compare silicone plastic 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.

Thermal Properties

Glass Transition Temperature

200 °C 390 °F

Maximum Temperature: Decomposition

480 °C 890 °F

Specific Heat Capacity

850 J/kg-K 0.2 BTU/lb-°F

Thermal Conductivity

0.35 W/m-K 0.2 BTU/h-ft-°F

Thermal Expansion

35 µm/m-K

Electrical Properties

Dielectric Strength (Breakdown Potential)

30 kV/mm 1.2 V/mil

Electrical Resistivity Order of Magnitude

12 10x Ω-m

Other Material Properties


1.9 g/cm3 120 lb/ft3

Elastic (Young's, Tensile) Modulus

9.0 GPa 1.3 x 106 psi

Tensile Strength: Ultimate (UTS)

38 MPa 5.4 x 103 psi

Common Calculations

Stiffness to Weight: Axial

2.6 points

Stiffness to Weight: Bending

36 points

Strength to Weight: Axial

5.5 points

Strength to Weight: Bending

13 points

Thermal Diffusivity

0.22 mm2/s

Thermal Shock Resistance

8.5 points

Followup Questions

Further Reading

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