FDM Polycarbonate vs. Plastic Polypropylene

Compare FDM Polycarbonate vs. Plastic Polypropylene strength, stiffness, weight and thermal properties.

Plastic PolypropyleneBulk polymer (molded or machined)

Mechanical	FDM Polycarbonate	Plastic Polypropylene
Yield strength	53.3MPa11.62x stronger	33MPa2
Ultimate tensile strength	53.3MPa1	not stated (yield given)
Flexural strength	89.4MPa1	not sourced
Elongation at break	9.2%1	not sourced
Young's modulus (stiffness)	2.39GPa11.65x stiffer	1.45GPa2
Density	range1,180–1,200kg/m³1	900kg/m³2
Strength to weight	44.8kN·m/kg22% higher	36.7kN·m/kg
Stiffness to weight	2.01MN·m/kg25% higher	1.61MN·m/kg
Poisson's ratio	base material0.383	base material0.424
Shear modulus	0.867GPa1.7x stiffer in shear	0.511GPa
Bulk modulus	3.33GPa10% higher	3.02GPa
Speed of sound	1,418m/s12% faster	1,269m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	FDM Polycarbonate	Plastic Polypropylene
Thermal conductivity	base material0.2W/m·K5	base material0.17–0.22W/m·K4
Thermal expansion	base material65µm/m·K5	base material80–100µm/m·K4
100 mm part over a 50 °C swing	325µm growth38% less	450µm growth
Specific heat	not sourced	not sourced
Heats up and cools (diffusivity)	not sourced	not sourced
Thermal shock resistance	42.5W/m49% more resistant	28.6W/m
Glass transition	108°C1	not sourced
Max service temperature	HDT 0.455 MPa105°C1	HDT 0.45 MPa90°C2

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

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Sources5 documents: UltiMaker, LyondellBasell, Covestro, INEOS Olefins & Polymers USA

FDM Polycarbonate: Ultimaker PC, 3D-printed specimens, XY (flat); 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 (file v5.00), April 20, 2022.
Plastic Polypropylene: LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values

1
Ultimaker PC Technical Data Sheet, v5.00UltiMakerarchived copyFDM Polycarbonate · Yield strength: typicalFDM Polycarbonate · Ultimate tensile strength: typical, peak stress (= stress at yield)FDM Polycarbonate · Flexural strength: typicalFDM Polycarbonate · Elongation at break: typicalFDM Polycarbonate · Young's modulus (stiffness): typicalFDM Polycarbonate · Density: rangeFDM Polycarbonate · Glass transition: typicalFDM Polycarbonate · Max service temperature: HDT 0.455 MPa (printed specimens)
2
Moplen HP501H Product DataLyondellBasellPlastic Polypropylene · Yield strength: typical, tensile stress at yield ISO 527Plastic Polypropylene · Young's modulus (stiffness): typical, tensile modulus ISO 527Plastic Polypropylene · Density: typical, 23 °C ISO 1183-1Plastic Polypropylene · Max service temperature: HDT 0.45 MPa (ISO 75B), unannealed
3
Engineering Polymers Part and Mold Design: Thermoplastics, A Design GuideCovestroarchived copyFDM Polycarbonate · Poisson's ratio: base material: polycarbonate family typical (Covestro Part and Mold Design guide, Table 3-1)
4
Typical Engineering Properties of PolypropyleneINEOS Olefins & Polymers USAarchived copyPlastic Polypropylene · Poisson's ratio: base material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)Plastic Polypropylene · Thermal conductivity: base material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)Plastic Polypropylene · Thermal expansion: base material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)
5
Makrolon 2405 Technical Data SheetCovestroFDM Polycarbonate · Thermal conductivity: base material: Covestro Makrolon 2405 injection-molding PC, typical, through-plane, 23 °CFDM Polycarbonate · Thermal expansion: base material: Covestro Makrolon 2405 injection-molding PC, typical, 23-55 °C, parallel

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

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

Questions

Mechanical

Is FDM Polycarbonate stronger than Plastic Polypropylene?

FDM Polycarbonate is stronger: its yield strength is 53.3 MPa against 33 MPa for Plastic Polypropylene (1.62x).

Which is lighter, FDM Polycarbonate or Plastic Polypropylene?

Plastic Polypropylene is lighter: 900 kg/m³ against 1,190 kg/m³ for FDM Polycarbonate.

Which is stiffer, FDM Polycarbonate or Plastic Polypropylene?

FDM Polycarbonate is stiffer: Young's modulus 2.39 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in FDM Polycarbonate deflects less under the same load.

Which is lighter for the same job, FDM Polycarbonate or Plastic Polypropylene?

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

Part that must be	FDM Polycarbonate	Plastic Polypropylene
Stiff rod or tie (tension)	lighter	25% heavier
Stiff beam (bending)	3% heavier	lighter
Stiff panel or plate	12% heavier	lighter
Strong rod or tie	lighter	22% heavier
Strong beam	lighter	4% heavier
Strong panel or plate	4% 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).

Thermal

Which conducts heat better, FDM Polycarbonate or Plastic Polypropylene?

FDM Polycarbonate conducts heat better: 0.2 W/m·K against 0.195 W/m·K for Plastic Polypropylene.

Which expands less with temperature?

FDM Polycarbonate expands less: 65 µm/m·K against 90 µm/m·K for Plastic Polypropylene.