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Polylactic Acid (PLA, Polylactide)

PLA is a thermoplastic, further classified as a polyester plastic. It has the highest heat capacity and the lowest thermal conductivity relative to other polyester plastics.

Mechanical Properties

Graph bars compare PLA to other materials. From top to bottom: polyester plastic, thermoplastics, and the entire database.

Elastic (Young's, Tensile) Modulus

3.5 GPa 0.51 x 106 psi

Elongation at Break

6.0 %

Flexural Modulus

4.0 GPa 0.58 x 106 psi

Flexural Strength

80 MPa 12 x 103 psi

Shear Modulus

2.4 GPa 0.35 x 106 psi

Strength to Weight Ratio

40 kN-m/kg

Tensile Strength: Ultimate (UTS)

50 MPa 7.3 x 103 psi

Other Material Properties


1.3 g/cm3 78 lb/ft3

Glass Transition Temperature

60 °C 140 °F

Heat Deflection Temperature At 455 kPa (66 psi)

65 °C 150 °F

Melting Onset (Solidus)

160 °C 320 °F

Specific Heat Capacity

1800 J/kg-K 0.43 BTU/lb-°F

Thermal Conductivity

0.13 W/m-K 0.075 BTU/h-ft-°F

Thermal Diffusivity

0.058 m2/s

Followup Questions

Further Reading

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

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

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