Plastic LCP GF30 vs. Plastic PEEK

Q: Is Plastic LCP GF30 stronger than Plastic PEEK?

Plastic LCP GF30 is stronger: its tensile strength is 115 MPa against yield strength 98 MPa for Plastic PEEK (17%).

Q: Which is lighter, Plastic LCP GF30 or Plastic PEEK?

Plastic PEEK is lighter: 1,300 kg/m³ against 1,610 kg/m³ for Plastic LCP GF30.

Q: Which is stiffer, Plastic LCP GF30 or Plastic PEEK?

Plastic LCP GF30 is stiffer: Young's modulus 11.5 GPa against 4 GPa for Plastic PEEK, so the same part in Plastic LCP GF30 deflects less under the same load.

Q: Which is lighter for the same job, Plastic LCP GF30 or Plastic PEEK?

For the same stiffness or strength: Plastic LCP GF30 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic PEEK is lighter for a strong rod or tie, strong beam, strong panel or plate.

Q: Which conducts heat better, Plastic LCP GF30 or Plastic PEEK?

Plastic LCP GF30 conducts heat better: 0.5 W/m·K against 0.29 W/m·K for Plastic PEEK.

Q: Which expands less with temperature?

Plastic LCP GF30 expands less: 20 µm/m·K against 55 µm/m·K for Plastic PEEK.

Compare Plastic LCP GF30 vs. Plastic PEEK strength, stiffness, weight and thermal properties.

Change either side

Plastic LCP GF30Bulk polymer (molded or machined)

Plastic PEEKBulk 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	not given (tensile used)	98MPasourcetypical, tensile yield
Ultimate tensile strength	115MPasourcetensile strength (ISO 527)	not sourced
Compressive strength	not sourced	125MPasourcetypical, 23 C
Flexural strength	184MPasourcetypical (ISO 178)	165MPasourcetypical, flexural stress at yield, 23 C
Elongation at break	1.5%sourcetensile elongation (ISO 527)	25%sourcetypical, at break
Young's modulus (stiffness)	11.5GPasourcetensile modulus (ISO 527)	4GPasourcetypical (nominal)
Density	1,610kg/m³sourcetypical	1,300kg/m³sourcetypical (crystalline)
Strength to weight	71.4kN·m/kg	75.4kN·m/kg6% higher
Stiffness to weight	7.14MN·m/kg2.32x higher	3.08MN·m/kg
Poisson's ratio	not sourced	0.38sourcetypical
Shear modulus	not sourced	1.45GPa
Bulk modulus	not sourced	5.56GPa
Speed of sound	2,673m/s	1,754m/s
Thermal
Thermal conductivity	0.5W/m·Ksourcehot disk (ISO 22007-2), temperature not stated	0.29W/m·Ksourcetypical, average, 23 C
Thermal expansion	20µm/m·Ksourceflow direction (MD), mean 50-150 °C	55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C)
100 mm part over a 50 °C swing	100µm growth2.75x less	275µm growth
Specific heat	839J/kg·KsourceASTM E1269, temperature not stated	2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012)
Heats up and cools (diffusivity)	0.37mm²/s3.65x faster	0.101mm²/s
Thermal shock resistance	not sourced	80.1W/m
Melting point	not sourced	343°Csourcetypical, DSC
Glass transition	not sourced	143°Csourceonset (midpoint 150 C)
Max service temperature	288°CsourceHDT 1.8 MPa (ISO 75)	240°CsourceUL 746B RTI, mechanical strength (continuous use index)
Values for	Sumitomo Chemical SUMIKASUPER LCP E6006L (30% glass fibre; high strength, low shrinkage); SUMIKASUPER LCP Technical Note, Version 04 / Nov. 2023, typical values.	Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07)

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 LCP GF30 stronger than Plastic PEEK?

Plastic LCP GF30 is stronger: its tensile strength is 115 MPa against yield strength 98 MPa for Plastic PEEK (17%).

Which is lighter, Plastic LCP GF30 or Plastic PEEK?

Plastic PEEK is lighter: 1,300 kg/m³ against 1,610 kg/m³ for Plastic LCP GF30.

Which is stiffer, Plastic LCP GF30 or Plastic PEEK?

Plastic LCP GF30 is stiffer: Young's modulus 11.5 GPa against 4 GPa for Plastic PEEK, so the same part in Plastic LCP GF30 deflects less under the same load.

Which is lighter for the same job, Plastic LCP GF30 or Plastic PEEK?

For the same stiffness or strength: Plastic LCP GF30 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic PEEK is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Plastic LCP GF30	Plastic PEEK
Stiff rod or tie (tension)	lighter	2.32x heavier
Stiff beam (bending)	lighter	37% heavier
Stiff panel or plate	lighter	15% heavier
Strong rod or tie	6% heavier	lighter
Strong beam	11% heavier	lighter
Strong panel or plate	14% heavier	lighter

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 LCP GF30 or Plastic PEEK?

Plastic LCP GF30 conducts heat better: 0.5 W/m·K against 0.29 W/m·K for Plastic PEEK.

Which expands less with temperature?