Plastic PLA vs. Rubber

Compare Plastic PLA vs. Rubber strength, stiffness, weight and thermal properties.

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RubberBulk polymer (molded or machined)

Mechanical
Try it on a partA bracket to run stress or thermal on, free in your browser	Open in LessCAD	Open in LessCAD
Yield strength	52.5MPasourcetypical	not given (tensile used)
Ultimate tensile strength	52.5MPasourcetypical, peak stress (= stress at yield)	23MPasourcetypical
Flexural strength	96.8MPasourcetypical	not sourced
Elongation at break	7.8%sourcetypical	830%sourcetypical106x more ductile
Young's modulus (stiffness)	3.25GPasourcetypical	not sourced
Density	1,240kg/m³sourcetypical	960kg/m³sourcetypical (specific gravity)
Strength to weight	42.3kN·m/kg1.77x higher	24kN·m/kg
Stiffness to weight	2.62MN·m/kg	not sourced
Poisson's ratio	not sourced	0.5sourcegovernment (NBS J. Res. 68A, 1964): computed by NBS for peroxide-cured gum NR vulcanizate, 25 °C, infinitesimal deformation0.49 in the solver: the linear element locks as the ratio nears 0.5 (nearly incompressible).
Shear modulus	not sourced	not sourced
Bulk modulus	not sourced	not sourced
Speed of sound	1,619m/s	not sourced
Thermal
Thermal conductivity	0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C	0.151W/m·Ksourcegovernment selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C
Thermal expansion	not sourced	not sourced
100 mm part over a 50 °C swing	not sourced	not sourced
Specific heat	1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C	1,881J/kg·Ksourcegovernment (NBS J. Res. 68A, Table 7; values observed for unvulcanized NR by Bekkedahl and Matheson), 25 °C
Heats up and cools (diffusivity)	0.0874mm²/s4% faster	0.0836mm²/s
Thermal shock resistance	not sourced	not sourced
Melting point	152°Csourcetypical	not sourced
Glass transition	59.1°Csourcetypical	not sourced
Max service temperature	58.8°CsourceHDT 0.455 MPa (printed specimens)	70°Csourcecontinuous use operating range
Values for	Ultimaker PLA, 3D-printed specimens, XY (flat) orientation; Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS dated April 20, 2022.	Weir Minerals Linatex Premium rubber (95 % natural rubber), typical physical properties, spec sheet WMD0118/202305

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Plastic PLA is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is Plastic PLA stronger than Rubber?

Plastic PLA is stronger: its yield strength is 52.5 MPa against tensile strength 23 MPa for Rubber (2.28x).

Which is lighter, Plastic PLA or Rubber?

Rubber is lighter: 960 kg/m³ against 1,240 kg/m³ for Plastic PLA.

Which is lighter for the same job, Plastic PLA or Rubber?

For the same stiffness or strength: Plastic PLA is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Plastic PLA	Rubber
Strong rod or tie	lighter	1.77x heavier
Strong beam	lighter	34% heavier
Strong panel or plate	lighter	17% heavier

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which is more ductile, Plastic PLA or Rubber?

Rubber stretches further before it breaks: 830% elongation at break against 7.8% for Plastic PLA.

Which conducts heat better, Plastic PLA or Rubber?

Rubber conducts heat better: 0.151 W/m·K against 0.13 W/m·K for Plastic PLA.

Among 72 materials

Stiffness against density

Strength against density