When choosing a 3D printing material, we usually start with the conditions that part must survive.
Does it need to be stiff? Flexible? Heat resistant? Tough enough to survive a fall? Can it handle moisture, chemicals, or a force, over and over?
That ensures that the part will do what it is supposed to do. But there’s another material property question that is rarely considered: how much carbon dioxide was required to create the material used to print the part?
The numbers vary by supplier, electricity source, recycled content, and accounting method, but the differences between materials can be substantial. After some looking, we came up with this chart:
| Material | Typical | Min | Max |
| PLA | 4.5 | 1.8 | 7.5 |
| PETG | 6 | 5.5 | 7.5 |
| ABS | 3.8 | 3.2 | 4.5 |
| ASA | 3.8 | 3.2 | 4.5 |
| TPU | 3.6 | 3.5 | 5 |
| Polypropylene (PP) | 2.5 | 2.4 | 6.5 |
| Polycarbonate (PC) | 4 | 3.9 | 6 |
| Nylon PA6/PA66 | 7.5 | 6.7 | 9.5 |
| Nylon PA12 | 10.5 | 6.9 | 15.4 |
| HIPS | 4.5 | 3.8 | 5.6 |
| PVA/PVOH support material | 3.7 | 1.6 | 5.8 |
| Recycled PLA (100%) | 1.2 | 0.5 | 1.8 |
| Recycled ABS | 1 | 0.2 | 1.5 |
| Recycled PETG | 2.6 | 2 | 3.5 |
A kilogram of plain PA6 or PA66 nylon typically requires roughly 7–9 kg of CO2 equivalent (CO2e). PA12 can be higher, with published estimates from about 7 to 15 kg.
That puts nylon near the high end of common 3D printing materials.
By comparison, ABS and ASA are around 3–4 kg CO2e per kilogram in the available data. TPU is roughly 3.5–5 kg. Polypropylene can be lower, at around 2.5 kg, although supplier-specific results vary.
PLA is more complicated. Some sources put it near 2 kg CO2e per kilogram, while other studies report far higher values. The result apparently depends partly on how the carbon absorbed by the original plant material is counted. PLA is made from renewable materials, but growing it, processing it, transporting it, and converting it into polymer still requires energy, sometimes supplied using CO2.
And there’s a psychological angle here too: that 1kg spool of PA12 you’re holding in your hand may have required TEN KILOGRAMS of CO2 to produce. Think about that when you are 3D printing.
So which materials are best for someone concerned about carbon emissions?
Recycled materials generally should be the best, although their mechanical properties can be less than non-recycled materials.
Recycled ABS can be around 1 kg CO2e per kilogram when made from clean industrial waste or ground-up scraps. Recycled PETG has been reported at around 2.5 kg, compared with nearly 6 kg for an equivalent virgin PETG. Recycled PLA can be around 1.2 kg when biogenic carbon is excluded from the calculation. Some accounting methods report an even lower, sometimes negative, result when temporarily stored plant-derived carbon is given credit. Calculating CO2e is a bit of a science, it turns out.
Those figures are of course estimates, since process and details vary considerably by manufacturer and product.
You should also know that the carbon footprint of a printed part includes more than the input material. The printer consumes electricity, and often need heated beds, heated chambers, drying, support structures, etc. Those can add more CO2e to the result.
This doesn’t mean nylon is a bad material. If its strength, flexibility, or durability lets a part last longer or replace a heavier manufactured component, its CO2e could be justified. However, engineering performance is the reason we print in the first place.
The CO2e of a material shouldn’t be the first factor considered when selecting a material. But if you have a choice between materials, and you’d like to contribute to reducing CO2, then pick a material with a lower CO2e.
Via EPDDanmark, Science Direct, Total Energies Corbion, Prusa
