Technical Guide: PP vs PET Geotextiles
Polypropylene (PP) and Polyester (PET) are the two most common polymers used in nonwoven geotextiles. While both are widely employed for filtration, separation, and drainage applications, their material characteristics can lead to notable performance differences depending on the project environment. This guide outlines the key differences and application considerations when choosing between PP and PET geotextiles.
1. Polymer Structure & Manufacturing
- PP Geotextiles
- Made from polypropylene staple fibres
- Typically needle-punched
- Lower density
- PET Geotextiles
- Made from continuous filament polyester
- Usually needle-punched and thermally bonded
- Higher density
2. Mechanical Performance
|
Property |
PP (InfraThread PP) |
PET (InfraThread PET) |
|
Tensile Strength |
Up to 50 kN/m |
Up to 50 kN/m |
|
Grab Tensile Strength |
Up to 3000 N |
Up to 3600 N |
|
CBR Puncture Strength |
Up to 7000 N |
Up to 9500 N |
|
Elongation |
~60% |
~60% |
Despite the lower density, high-weight PP geotextiles can offer comparable tensile and puncture resistance to PET equivalents.
3. Hydraulic Properties
|
Property |
PP |
PET |
|
Pore Size (O90/O95) |
50–90 µm |
70–110 µm |
|
Water Flow Rate (Q100) |
80–160 L/m²/s |
40–235 L/m²/s |
PET geotextiles typically have higher water flow rates, making them favourable for drainage applications, while PP offers finer filtration.
4. Environmental Resistance
|
Condition |
PP |
PET |
|
UV Resistance |
Requires additives |
Inherently more resistant |
|
Chemical Resistance |
Excellent in alkaline |
Better in acidic |
|
Temperature Stability |
Up to ~120°C |
Up to ~200°C |
|
Water Absorption |
None (hydrophobic) |
Minimal |
|
Wet-Dry Cycling |
Stable when buried |
Stable when buried |
5. Practical Considerations
|
Factor |
PP |
PET |
|
Roll Width (typical) |
3.95 m* |
6.0 m* |
|
Creep Resistance |
Lower |
Higher |
|
Dimensional Stability |
High |
Slight water expansion |
|
Weight Equivalency |
1000gsm PP ≈ 1200gsm PET |
Due to density difference |
* Widths for both PP and PET geotextiles can be customized depending on project requirements.
6. Recommended Applications
|
Application Type |
Preferred Material |
|
Subsoil drainage & wrapped drains |
PET |
|
Filtration in fine soils |
PP |
|
High-temperature or UV-exposed surfaces |
PET |
|
Alkaline tailings or marine exposure |
PP |
|
Landfill capping or reinforcement |
Either (grade dependent) |
Conclusion
Both PP and PET geotextiles serve critical roles in civil and environmental engineering, and the choice depends on specific site conditions. PET offers better thermal and UV performance with faster installation advantages, while PP stands out in chemical resistance and fine filtration. Both materials perform well under wet-dry cycling when properly covered and confined.
Our Recommendation
At Geosynthetics Australia, we offer the InfraThread series of high-performance nonwoven geotextiles in both PP and PET options. Whether you're working on roadworks, drainage layers, or landfill containment, our InfraThread range is engineered to meet Australian conditions with robust mechanical and hydraulic performance.
- InfraThread PP: Ideal for alkaline or marine environments and fine soil filtration
- InfraThread PET: Preferred for drainage, thermal exposure, and high UV resistance
For help selecting the best grade for your project, contact our team for specification support.
