LLDPE vs PEX
Polymer · grade comparison
LLDPE and PEX are both polymer grades. PEX is the stronger of the two: yield strength 17 MPa (2.47 ksi) against 11 MPa (1.6 ksi) for LLDPE, about 55% more. In exchange, LLDPE is the more ductile: elongation 700% versus 500% for PEX, and PEX is harder (60 Shore D vs 50 Shore D). PEX is stiffer (0.68 GPa vs 0.25 GPa) and PEX runs hotter in service (95°C vs 80°C continuous). On the shop floor, LLDPE machines more easily (good vs fair), LLDPE welds better (excellent vs not recommended), and LLDPE sits in a lower cost tier (budget, $) than PEX (standard, $$).
LLDPEChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
PEXChoose it when strength drives the design, or when the part sees heat.
LLDPE vs PEX: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore A
Hardness, Shore D
Hardness, Rockwell R
Tear Strength
Same in both: Poisson's Ratio 0.45
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (Saturation)
Refractive Index
Same in both: Water Absorption (24 h) 0.01%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Limiting Oxygen Index
Max Service Temperature (short-term)
Same in both: Specific Heat Capacity 2,300 J/kg·K0.55 BTU/lb·°F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dissipation Factor (1 MHz)
Volume Resistivity
Same in both: Dielectric Strength 25 kV/mm635 V/mil · Dielectric Constant (1 MHz) 2.3 · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 25 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Polishability
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Formability (cold) 90 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Same in both: Thermal Diffusivity 0.2 mm²/s · 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.
Manufacturing and finishing
| Capability | LLDPE | PEX |
|---|---|---|
| Default condition | — | — |
| Relative cost | $ Budget | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
LLDPE vs PEX — frequently asked
Is PEX stronger than LLDPE?
Yes. PEX has a typical yield strength of 17 MPa (2.47 ksi) against 11 MPa (1.6 ksi) for LLDPE — about 55% more. Tensile strength is 22 MPa (3.19 ksi) vs 25 MPa (3.63 ksi).
Which is cheaper, LLDPE or PEX?
LLDPE is the lower-cost material: it sits in the budget tier ($) while PEX is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, LLDPE or PEX?
LLDPE. Its machinability rates good (55/100) against fair (42/100) for PEX; for welding the order is LLDPE first (excellent, 90/100) then PEX (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in LLDPE and PEX 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.