document updated 12 years ago, on Feb 26, 2012
Different methods used to determine the type of plastic, when the type is originally unknown.
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[2]
Decision tree
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this is what it looks like if you get a green flame
boiling water test
When placed in boiling water for 30 seconds, does the material soften?
Soften: PET, ?
Doesn't soften: ?
burn test
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does it float in water?
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Floats: PP, LDPE, HDPE
Sinks: PS, PVC, PET
solubility
Some plastics are soluable (S) in a given solvent, some plastics will swell (SW), and some plastics are insoluable (I):
| Gasoline | Toluene | Acetone | Cyclohexanone
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| ABS | SW | S | S | S
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| LDPE, HDPE | I | I | I | I
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| PA (polyamides) | I | I | I | I
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| PET | I | I | I | I
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| PMMA | I | SW | S | S
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| PP | I | I | I | I
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| PPO | I | SW | S | S
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| PS | S | S | S | S
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| PVC | I | SW | SW | S
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