Which plastics are resistant to high mechanical stress?
Which plastics have mechanical resistance? Tensile strength, compressive strength, rigidity & other properties.
Materials have developed over recent decades from simple everyday materials into highly specialised plastics that are used in the most demanding industrial applications. One of the central properties that designers and engineers look at is mechanical load-bearing capacity. But which plastics really withstand the high demands?
What does "mechanical load-bearing capacity" mean for plastics?
The term "mechanical load-bearing capacity" refers to a material's ability to withstand mechanical forces such as tension, compression, bending and impact stress without being permanently deformed or destroyed. This property is particularly relevant in industries such as mechanical engineering, automotive engineering, aerospace or medical technology.
The following mechanical properties play a decisive role here:
- Tensile strength: resistance to tensile load
- Flexural strength: resistance to deflection
- Impact strength: energy absorption under sudden load
- Stiffness: resistance to elastic deformation
Particularly load-bearing plastics in comparison
The following table provides an overview of selected plastics with high mechanical load-bearing capacity and their typical characteristic values:
| Plastic | Tensile strength (MPa) | Impact strength (kJ/m²) | Stiffness (GPa) | Remark |
|---|---|---|---|---|
| PEEK | up to 100 | > 55 | approx. 3.6 | Heat-resistant, chemically resistant |
| PA (polyamide) | 60–90 | 5–20 | 2.5–3.0 | Good abrasion resistance, tough |
| PC (polycarbonate) | 60–70 | > 80 | 2.2–2.4 | Very impact-resistant, transparent |
| POM | 60–70 | 5–10 | 2.5–3.0 | Low friction, high dimensional stability |
| PPSU | 55–65 | > 50 | approx. 2.4 | Thermally and mechanically load-bearing |
| PEI | 80–90 | 10–20 | 3.2–3.5 | High strength combined with good dimensional stability |
When are high-load-bearing plastics used?
Mechanically load-bearing plastics are used in particular when metals are out of the question due to weight, corrosion or processing. Examples of typical applications:
- Mechanical and plant engineering: gears, bearings, guides
- Automotive industry: structural parts, clips, bearing bushes
- Aerospace: lightweight components with high strength
- Medical technology: components in surgical instruments or devices
Advantages over conventional materials
Mechanically load-bearing plastics offer numerous advantages over metal or ceramics:
- Low weight with high strength
- Corrosion and chemical resistance
- Easier processing by injection moulding or CNC machining
- High fatigue strength even under alternating loads
Selection criteria for designers
The selection of the right plastic depends not only on the maximum load-bearing capacity but also on environmental conditions and other requirements. The following aspects should be included:
- Temperature range (thermal load-bearing capacity)
- Contact with chemicals or UV radiation
- Requirements for friction or wear
- Cost-effectiveness and availability
Conclusion: making targeted use of plastic mechanical load-bearing capacity
Mechanical load-bearing capacity is a decisive factor in material selection for technical applications. Modern high-performance plastics such as PEEK, PA or PEI combine high strength with other advantages such as low weight and chemical resistance. Through targeted selection, durable, high-performance and economically attractive components can be realised.
