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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. The graph bars on the material properties cards below compare PLA to: polyester plastics (top), all thermoplastics (middle), and the entire database (bottom).

Mechanical Properties

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

Tensile Strength: Ultimate (UTS)

50 MPa 7.3 x 103 psi

Other Material Properties

Density

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

Common Calculations

Stiffness to Weight: Axial

1.6 points

Stiffness to Weight: Bending

40 points

Strength to Weight: Axial

11 points

Strength to Weight: Bending

24 points

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