Plastic PMMA vs. Plastic UHMWPE

Compare Plastic PMMA vs. Plastic UHMWPE strength, stiffness, weight and thermal properties.

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Plastic PMMABulk polymer (molded or machined)

Plastic UHMWPEBulk polymer (molded or machined)

Mechanical
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Yield strength	not given (tensile used)	20MPasourcetypical, tensile stress at yield ISO 527, 50 mm/min
Ultimate tensile strength	80MPasourcetypical, 23 °C	43MPasourcetypical, tensile stress at break ISO 527, 50 mm/min
Compressive strength	110MPasourcecompressive yield stress, typical	not sourced
Flexural strength	115MPasourcetypical	not sourced
Elongation at break	5.5%sourcetypical	465%sourcetypical, nominal elongation at break ISO 527
Young's modulus (stiffness)	3.3GPasourcetypical, short-term	0.66GPasourcetypical, tensile modulus ISO 527, 1 mm/min
Density	1,190kg/m³sourcetypical	930kg/m³sourcetypical28% lighter
Strength to weight	67.2kN·m/kg3.13x higher	21.5kN·m/kg
Stiffness to weight	2.77MN·m/kg3.91x higher	0.71MN·m/kg
Poisson's ratio	0.37sourcetypical	not sourced
Shear modulus	1.2GPa	not sourced
Bulk modulus	4.23GPa	not sourced
Speed of sound	1,665m/s	842m/s
Thermal
Thermal conductivity	0.19W/m·Ksourcetypical	0.4W/m·Ksourcetypical, unfilled (narrative value, generic Celanese UHMWPE)
Thermal expansion	70µm/m·Ksource0-50 °C	200µm/m·Ksourcetypical, 20 to 100 °C (generic Celanese UHMWPE)
100 mm part over a 50 °C swing	350µm growth2.86x less	1,000µm growth
Specific heat	1,470J/kg·Ksourcetypical	not sourced
Heats up and cools (diffusivity)	0.109mm²/s	not sourced
Thermal shock resistance	41.5W/m	not sourced
Melting point	not sourced	130–138°CsourceDSC 10 K/min
Max service temperature	80°Csourcemax. permanent service temperature	80°Csourcerecommended max constant operating temperature
Values for	Röhm PLEXIGLAS GS 0F00 cast acrylic sheet, typical values at 23 °C / 50 % RH (Röhm Technical Information Ref. No. 211-1)	Celanese GUR 4120 (avg. molecular weight 4.7x10^6 g/mol), typical values on compression-molded specimens; CTE and thermal conductivity from Celanese's generic UHMWPE guide (grade not named)

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.

Questions

Is Plastic PMMA stronger than Plastic UHMWPE?

Plastic PMMA is stronger: its tensile strength is 80 MPa against yield strength 20 MPa for Plastic UHMWPE (4x).

Which is lighter, Plastic PMMA or Plastic UHMWPE?

Plastic UHMWPE is lighter: 930 kg/m³ against 1,190 kg/m³ for Plastic PMMA.

Which is stiffer, Plastic PMMA or Plastic UHMWPE?

Plastic PMMA is stiffer: Young's modulus 3.3 GPa against 0.66 GPa for Plastic UHMWPE, so the same part in Plastic PMMA deflects less under the same load.

Which is lighter for the same job, Plastic PMMA or Plastic UHMWPE?

For the same stiffness or strength: Plastic PMMA is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Plastic PMMA	Plastic UHMWPE
Stiff rod or tie (tension)	lighter	3.91x heavier
Stiff beam (bending)	lighter	1.75x heavier
Stiff panel or plate	lighter	34% heavier
Strong rod or tie	lighter	3.13x heavier
Strong beam	lighter	1.97x heavier
Strong panel or plate	lighter	1.56x 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 conducts heat better, Plastic PMMA or Plastic UHMWPE?

Plastic UHMWPE conducts heat better: 0.4 W/m·K against 0.19 W/m·K for Plastic PMMA.

Which expands less with temperature?

Plastic PMMA expands less: 70 µm/m·K against 200 µm/m·K for Plastic UHMWPE.

Among 72 materials

Stiffness against density

Strength against density