Silicone rubber
Density of silicone rubber
1,250 kg/m³ (1,100–1,500)
1.25 g/cm³ · 78.0 lb/ft³
Its backbone is silicon and oxygen rather than carbon, which is why it stays rubbery from about -60 °C to +230 °C where every carbon-based rubber has either frozen solid or decomposed. It is weak in tension — 5-10 MPa against natural rubber's 20-30 — so it is never used for drive belts or tyres. It is also permeable to gases, which rules it out for compressed-gas seals but is exactly what makes silicone contact lenses breathable.
Properties
- Density
- 1,250 kg/m³ (1,100–1,500) — 1.25 g/cm³
- Tensile strength
- 5–10 MPa
- Young's modulus
- 0.005 GPa
- Thermal conductivity
- 0.2 W/(m·K)
- Thermal expansion
- 250 µm/(m·K)
- Floats in water
- No
- Magnetic
- No
What it is used for
- Oven and bakeware moulds
- High-temperature gaskets and O-rings
- Medical tubing and implants
- Sealant around baths and windows
How it compares
Water is 1,000 kg/m³. Anything with a shorter bar than water floats in it.
air 1.2 kg/m³
expanded polystyrene foam 20 kg/m³
rigid polyurethane foam 40 kg/m³
Water — the float line 1,000 kg/m³
silicone rubber 1,250 kg/m³
tungsten 19,250 kg/m³
gold 19,300 kg/m³
platinum 21,450 kg/m³
| Material | Density | Relative to water |
|---|---|---|
| rigid polyurethane foam | 40 kg/m³ | 0.04× |
| expanded polystyrene foam | 20 kg/m³ | 0.02× |
| air | 1.2 kg/m³ | 0.00× |
| silicone rubber ← | 1,250 kg/m³ | 1.25× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |
Does it rust?
Silicone rubber contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.
Is it magnetic?
Silicone rubber is not a metal and has no ferromagnetic response.
Common questions
- What is the density of silicone rubber?
- 1,250 kg/m³ (1,100–1,500), or 1.25 g/cm³.
- Does silicone rubber float?
- No. At 1,250 kg/m³ it is denser than water.
- Is silicone rubber magnetic?
- Silicone rubber is not a metal and has no ferromagnetic response.
Related pages
- Does silicone rubber float? No
- PLA 1,240 kg/m³
- ABS 1,050 kg/m³
- Acrylic (PMMA) 1,180 kg/m³
- Polycarbonate 1,200 kg/m³
- Polypropylene 905 kg/m³
- PTFE 2,170 kg/m³
- Rigid PVC 1,400 kg/m³
- HDPE 955 kg/m³
Sources
- Typical range compiled from manufacturer specifications — At One Place