Plastic Nylon vs. Plastic Polypropylene

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

Plastic PolypropyleneBulk polymer (molded or machined)

Mechanical	Plastic Nylon	Plastic Polypropylene
Yield strength	63.1MPa11.91x stronger	33MPa2
Ultimate tensile strength	63.1MPa1	not stated (yield given)
Flexural strength	82.9MPa1	not sourced
Elongation at break	not sourced	not sourced
Young's modulus (stiffness)	2.33GPa11.61x stiffer	1.45GPa2
Density	1,140kg/m³1	900kg/m³227% lighter
Strength to weight	55.4kN·m/kg1.51x higher	36.7kN·m/kg
Stiffness to weight	2.04MN·m/kg27% higher	1.61MN·m/kg
Poisson's ratio	base material0.43	base material0.424
Shear modulus	0.833GPa1.63x stiffer in shear	0.511GPa
Bulk modulus	3.89GPa29% higher	3.02GPa
Speed of sound	1,430m/s13% 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	Plastic Nylon	Plastic Polypropylene
Thermal conductivity	base material0.33W/m·K5	base material0.17–0.22W/m·K4
Thermal expansion	base material98–102µm/m·K5	base material80–100µm/m·K4
100 mm part over a 50 °C swing	500µm growth	450µm growth11% less
Specific heat	base material1,700J/kg·K5	not sourced
Heats up and cools (diffusivity)	0.17mm²/s	not sourced
Thermal shock resistance	53.6W/m1.87x more resistant	28.6W/m
Melting point	188°C1	not sourced
Glass transition	55.1°C1	not sourced
Max service temperature	HDT 0.455 MPa89.2°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, BASF

Plastic Nylon: Ultimaker Nylon, 3D-printed specimens, XY (flat), conditioned >=24 h at room temperature; 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 v2.00, April 20, 2022.
Plastic Polypropylene: LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values

1
Ultimaker Nylon Technical Data Sheet, v5.00UltiMakerarchived copyPlastic Nylon · Yield strength: typicalPlastic Nylon · Ultimate tensile strength: typical, peak stress (= stress at yield)Plastic Nylon · Flexural strength: typicalPlastic Nylon · Young's modulus (stiffness): typicalPlastic Nylon · Density: typicalPlastic Nylon · Melting point: typicalPlastic Nylon · Glass transition: typicalPlastic Nylon · 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 GuideCovestroPlastic Nylon · Poisson's ratio: base material: unfilled polyamide (PA), conditioned, maker design-guide family value (Covestro 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
Ultramid (PA) Product RangeBASFPlastic Nylon · Thermal conductivity: base material: unreinforced BASF Ultramid PA66 (A3K) and PA6 (B3S), 23 C (same value for both)Plastic Nylon · Thermal expansion: base material: unreinforced BASF Ultramid PA66 (A3K, 98) and PA6 (B3S, 102), 23-55 CPlastic Nylon · Specific heat: base material: unreinforced BASF Ultramid PA66 (A3K) and PA6 (B3S), 23 C (same value for both)

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.

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

Questions

Mechanical

Is Plastic Nylon stronger than Plastic Polypropylene?

Plastic Nylon is stronger: its yield strength is 63.1 MPa against 33 MPa for Plastic Polypropylene (1.91x).

Which is lighter, Plastic Nylon or Plastic Polypropylene?

Plastic Polypropylene is lighter: 900 kg/m³ against 1,140 kg/m³ for Plastic Nylon.

Which is stiffer, Plastic Nylon or Plastic Polypropylene?

Plastic Nylon is stiffer: Young's modulus 2.33 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in Plastic Nylon deflects less under the same load.

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

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

Part that must be	Plastic Nylon	Plastic Polypropylene
Stiff rod or tie (tension)	lighter	27% heavier
Stiff beam (bending)	about equal	about equal
Stiff panel or plate	8% heavier	lighter
Strong rod or tie	lighter	1.51x heavier
Strong beam	lighter	22% heavier
Strong panel or plate	lighter	9% 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).

Thermal

Which conducts heat better, Plastic Nylon or Plastic Polypropylene?

Plastic Nylon conducts heat better: 0.33 W/m·K against 0.195 W/m·K for Plastic Polypropylene.

Which expands less with temperature?

Plastic Polypropylene expands less: 90 µm/m·K against 100 µm/m·K for Plastic Nylon.