FabDigit

PP vs HDPE and 2 more: properties

PPHDPELDPEPVC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

1.5 GPa0.22 Msi
1.1 GPa0.16 Msi
0.22 GPa0.03 Msi
3 GPa0.44 Msi

Shear Modulus

0.55 GPa0.08 Msi
0.4 GPa0.06 Msi
0.08 GPa0.01 Msi
1.1 GPa0.16 Msi

Bulk Modulus

3 GPa0.45 Msi
3 GPa0.44 Msi
2 GPa0.26 Msi
4 GPa0.61 Msi

Poisson's Ratio

0.42
0.44
0.45
0.38

Tensile Strength (Ultimate)

35 MPa5.1 ksi
28 MPa4.1 ksi
11 MPa1.6 ksi
52 MPa7.5 ksi

Yield Strength (0.2% offset)

33 MPa4.8 ksi
26 MPa3.8 ksi
10 MPa1.5 ksi
50 MPa7.3 ksi

Elongation at Break

150%
600%
450%
45%

Compressive Strength

42 MPa6.1 ksi
22 MPa3.2 ksi
9 MPa1.3 ksi
68 MPa9.9 ksi

Compressive Modulus

1.4 GPa0.2 Msi
0.9 GPa0.13 Msi
0.2 GPa0.03 Msi
2.9 GPa0.42 Msi

Flexural Strength

45 MPa6.5 ksi
27 MPa3.9 ksi
10 MPa1.5 ksi
90 MPa13.1 ksi

Flexural Modulus

1.5 GPa0.22 Msi
1.2 GPa0.17 Msi
0.25 GPa0.04 Msi
3 GPa0.44 Msi

Shear Strength

25 MPa3.6 ksi
20 MPa2.9 ksi
8 MPa1.2 ksi
41 MPa5.9 ksi

Fracture Toughness (K_IC)

3.5 MPa·√m3.2 ksi·√in
2 MPa·√m1.8 ksi·√in
1.4 MPa·√m1.3 ksi·√in
2.5 MPa·√m2.3 ksi·√in

Izod Impact, Notched

30 J/m0.56 ft·lbf/in
90 J/m1.7 ft·lbf/in
800 J/m15 ft·lbf/in
55 J/m1 ft·lbf/in

Hardness, Shore D

72 Shore D
65 Shore D
47 Shore D
82 Shore D

Hardness, Rockwell R

95 HRR
55 HRR
110 HRR

Hardness, Shore A

93 Shore A

Tear Strength

55 kN/m314 lbf/in

Physical

Density and transition temperatures.

Density

0.91 g/cm³0.03 lb/in³
0.96 g/cm³0.03 lb/in³
0.92 g/cm³0.03 lb/in³
1.42 g/cm³0.05 lb/in³

Melting Temperature (Tm)

165°C329 °F
132°C270 °F
110°C230 °F

Glass Transition (Tg)

-10°C14 °F
-110°C-166 °F
-110°C-166 °F
80°C176 °F

Water Absorption (24 h)

0.02%
0.01%
0.01%
0.06%

Water Absorption (Saturation)

0.1%
0.05%
0.02%
0.2%

Refractive Index

1.49
1.54
1.51
1.54

Light Transmission

80%

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.22 W/m·K0.13 BTU/hr·ft·°F
0.48 W/m·K0.28 BTU/hr·ft·°F
0.33 W/m·K0.19 BTU/hr·ft·°F
0.16 W/m·K0.09 BTU/hr·ft·°F

Specific Heat Capacity

1,900 J/kg·K0.45 BTU/lb·°F
1,900 J/kg·K0.45 BTU/lb·°F
2,100 J/kg·K0.5 BTU/lb·°F
950 J/kg·K0.23 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

110 µm/m·K61.1 µin/in·°F
150 µm/m·K83.3 µin/in·°F
190 µm/m·K106 µin/in·°F
65 µm/m·K36.1 µin/in·°F

Max Service Temperature (continuous)

100°C212 °F
80°C176 °F
70°C158 °F
60°C140 °F

Min Service Temperature

-10°C14 °F
-80°C-112 °F
-60°C-76 °F
-10°C14 °F

Heat Deflection Temp. @ 0.45 MPa

105°C221 °F
76°C169 °F
47°C117 °F
75°C167 °F

Heat Deflection Temp. @ 1.8 MPa

60°C140 °F
47°C117 °F
34°C93 °F
68°C154 °F

Vicat Softening Point (B50)

90°C194 °F
76°C169 °F
50°C122 °F
80°C176 °F

Limiting Oxygen Index

18%
18%
18%
45%

Max Service Temperature (short-term)

130°C266 °F
110°C230 °F
90°C194 °F
80°C176 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁴ Ω·m3.94×10²¹ µΩ·in
1×10¹⁴ Ω·m3.94×10²¹ µΩ·in
1×10¹⁴ Ω·m3.94×10²¹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in

Dielectric Strength

25 kV/mm635 V/mil
24 kV/mm610 V/mil
25 kV/mm635 V/mil
22 kV/mm559 V/mil

Dielectric Constant (1 MHz)

2.25
2.35
2.28
3.1

Dissipation Factor (1 MHz)

3×10⁻⁴
3×10⁻⁴
3×10⁻⁴
0.015

Volume Resistivity

1×10¹⁶ Ω·cm
1×10¹⁶ Ω·cm
1×10¹⁶ Ω·cm
1×10¹⁵ Ω·cm

Surface Resistivity

1×10¹⁵ Ω
1×10¹⁵ Ω
1×10¹⁵ Ω
1×10¹⁴ Ω

Same in both: Comparative Tracking Index (CTI) 600 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

92 / 100
90 / 100
88 / 100
90 / 100

UV / Weathering Resistance

20 / 100
25 / 100
20 / 100
55 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

60 / 100
75 / 100
45 / 100
85 / 100

Weldability

92 / 100
95 / 100
95 / 100
90 / 100

Formability (cold)

80 / 100
70 / 100
90 / 100
80 / 100

Polishability

40 / 100
30 / 100
30 / 100
60 / 100

Mold Shrinkage

1.6%
2%
2.5%
0.4%

Melt Flow Rate

12 g/10 min
8 g/10 min
2 g/10 min

Processing Melt Temperature (typ.)

230°C446 °F
230°C446 °F
190°C374 °F
185°C365 °F

Mold Temperature (typ.)

40°C104 °F
40°C104 °F
30°C86 °F
40°C104 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

78 MJ/kg33,534 BTU/lb
78 MJ/kg33,534 BTU/lb
80 MJ/kg34,394 BTU/lb
67 MJ/kg28,805 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
2 kg CO₂/kg
2.1 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

100 L/kg12 gal/lb
90 L/kg10.8 gal/lb
120 L/kg14.4 gal/lb
120 L/kg14.4 gal/lb

Typical Recycled Content

5%
10%
10%
10%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

39 kN·m/kg
29 kN·m/kg
12 kN·m/kg
37 kN·m/kg

Specific Stiffness (E / density)

1.7 MN·m/kg
1.2 MN·m/kg
0.2 MN·m/kg
2.1 MN·m/kg

Modulus of Resilience

363 kJ/m³
307 kJ/m³
227 kJ/m³
417 kJ/m³

Thermal Diffusivity

0.1 mm²/s
0.3 mm²/s
0.2 mm²/s
0.1 mm²/s

Same in both: Thermal Shock Resistance Index 0

Strength versus weight

Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scaleHDPELDPEPPPVC

Manufacturing and finishing

CapabilityPPHDPELDPEPVC
CNC machiningYesYesYes
3D printingYes
Default conditionHomopolymerFDA CompliantUnfilledRigid (Type I)
Relative cost$ Budget$ Budget$ Budget$ Budget
Min. machined wall0.5 mm0.5 mm0.5 mm
Best machined surfaceRa 0.8 µmRa 0.8 µmRa 0.8 µm
Conductive CoatingYes
Dyeing (Nylon)Yes
Primer CoatingYes
Tinted CoatingYes
Vacuum MetallizationYes
Waterproof CoatingYes

Both are offered for Sheet metal and Injection molding. They share 6 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Painting, Soft Touch Coating, Spray Painting, UV Coating.

Ready to make it?

Upload a CAD file and FabDigit prices the part in PP and HDPE side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.