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Polyarylate (PAR)

PAR is an otherwise-unclassified thermoplastic material. The graph bars on the material properties cards below compare PAR to: otherwise unclassified thermoplastics (top), all thermoplastics (middle), 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

93 MPa 13 x 103 psi

Elastic (Young's, Tensile) Modulus

2.0 GPa 0.29 x 106 psi

Elongation at Break

50 %

Flexural Modulus

2.1 GPa 0.3 x 106 psi

Flexural Strength

75 MPa 11 x 103 psi

Impact Strength: Notched Izod

220 J/m 4.1 ft-lb/in

Rockwell R Hardness


Tensile Strength: Ultimate (UTS)

67 MPa 9.7 x 103 psi

Thermal Properties

Glass Transition Temperature

190 °C 370 °F

Heat Deflection Temperature At 1.82 MPa (264 psi)

170 °C 350 °F

Heat Deflection Temperature At 455 kPa (66 psi)

180 °C 360 °F

Maximum Temperature: Decomposition

470 °C 880 °F

Specific Heat Capacity

1200 J/kg-K 0.29 BTU/lb-°F

Thermal Conductivity

0.18 W/m-K 0.1 BTU/h-ft-°F

Thermal Expansion

88 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 Hz


Dielectric Strength (Breakdown Potential)

16 kV/mm 0.63 V/mil

Electrical Resistivity Order of Magnitude

12 10x Ω-m

Otherwise Unclassified Properties


1.2 g/cm3 75 lb/ft3

Limiting Oxygen Index (LOI)

35 %

Water Absorption After 24 Hours

0.26 %

Common Calculations

Stiffness to Weight: Axial

0.93 points

Stiffness to Weight: Bending

35 points

Strength to Weight: Axial

16 points

Strength to Weight: Bending

31 points

Thermal Diffusivity

0.13 mm2/s

Thermal Shock Resistance

27 points

Followup Questions

Further Reading

SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000

Modern Plastics Handbook, Charles A. Harper (editor), 1999

Plastics Materials, 7th ed., J. A. Brydson, 1999