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Diallyl Phthalate (DAP)

DAP is a thermoset plastic. It has the lowest tensile strength among thermoset plastics. In addition, it has the lowest mechanical heat stability and a fairly high dielectric strength. The graph bars on the material properties cards below compare DAP 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

150 MPa 22 x 103 psi

Elastic (Young's, Tensile) Modulus

13 GPa 1.8 x 106 psi

Elongation at Break

31 %

Flexural Strength

62 MPa 9.0 x 103 psi

Impact Strength: Notched Izod

14 J/m 0.26 ft-lb/in

Tensile Strength: Ultimate (UTS)

28 MPa 4.0 x 103 psi

Thermal Properties

Glass Transition Temperature

150 °C 300 °F

Heat Deflection Temperature At 1.82 MPa (264 psi)

160 °C 310 °F

Specific Heat Capacity

1450 J/kg-K 0.35 BTU/lb-°F

Thermal Conductivity

0.6 W/m-K 0.35 BTU/h-ft-°F

Thermal Expansion

25 µm/m-K

Other Material Properties


1.7 g/cm3 110 lb/ft3

Dielectric Constant (Relative Permittivity) At 1 Hz


Dielectric Strength (Breakdown Potential)

40 kV/mm 1.6 V/mil

Electrical Resistivity Order of Magnitude

13 10x Ω-m

Common Calculations

Stiffness to Weight: Axial

4.1 points

Stiffness to Weight: Bending

46 points

Strength to Weight: Axial

4.5 points

Strength to Weight: Bending

12 points

Thermal Diffusivity

0.24 mm2/s

Thermal Shock Resistance

6.3 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