Polyethylene terephthalate vs Soda-lime glass
Polyethylene terephthalate and Soda-lime glass are genuine alternatives to one another — a choice somebody actually makes — and differ on 1 measured property, density most clearly.
Polyethylene terephthalate vs Soda-lime glass
Polyethylene terephthalate
The polyester in every drinks bottle and most clothing — and the only plastic with a genuinely working recycling stream.
Soda-lime glass
The commonest glass — silica with soda to lower its melting point and lime to stop it dissolving in water.
| Property | Polyethylene terephthalate | Soda-lime glass |
|---|---|---|
| Crystal system Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | amorphous |
| Density | 1.38–1.4 g/cm³ | 2.44–2.55 g/cm³ higher |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | 250–260 °C | Not known |
Choosing between them
Polyethylene terephthalate is recorded as a substitute for Soda-lime glass — lighter, cheaper.
What it gives up: A worse oxygen barrier, which is why wine and beer stayed in glass.
In this application, on the evidence cited above.