PVC is denser than ABS. Just immerse a piece of the plastic in a glass containing a solution of 2 tablespoons of salt in 8 ounces of water. If it stays on the bottom it is PVC. If it floats it is ABS.

Probably the easiest test if FTIR - whereas PVC has practically zero absorption at 1500-2800 1/cm, in the case of ABS a strong band at 2250 1/cm is observed due to acrylonitrile group.

Obviously, element analysis for N and Cl will give the answer as well, if you have access to it.

I assume the UV absorption of ABS should be stronger, but I cannot find the spectra at the moment.

From the easier tests, the density of PVC is normally higher, but you should be careful about homogeneity of the sample: porous/foamed material will definitely have different density.

Another very simple test is burning. In the external flame, both PVC and ABS burn, however, after elimination of the flame source ABS continues burning, whereas PVC USUALLY blows out (some types of PVC can keep burning). In the case of ABS the flame is smoky, and the smell is somewhat sweetish; in the case of PVC the flame is oftem greenish at the edge, and the smell is harch due to HCl release. (CAREFUL!)

Hope this helps.

the ABS is a copolymer with 2 glass transitions one in - 80º C aprox ant the other between 110º C and 125º C. The PVC has only one between 75 and 105 ºC. (a technique like TMA, DMA, DSC or DETA) could tell you with kind of polymer you have. In a DSC experiment you can see also in the PVC the gelled and non gelled part after the curing.

I am sorry. I did not see that you are asking to diferenciate beteen ABS and PVC without any lab tool. There is a way I think. The ABS has a degradation temperature (one step)of 375º C at 20º C/min. The PVC has a degradation temperature (2 steps) of 275º C. If you have a furnace at 300º C and you will weight the sample prior to put it into the furnace and after 30 min. the PVC will have a weight loss between 30 % and 60 % percent and the ABS will not have an apreciate weight loss.

Take a copper wire, heat it up and touch the plastic. Then take the copper wire with the plastic residue into a flame. In the case of PVC you should see green color in the flame because copper chlorides are relatively volatile under such conditions. You even don't need a spectrometer. This is a calssical method for detecting organic chlorine.

Great answers all of you, thank you.

I am not sure, if it is fulfil your request for lab-free test, however You can try solubility test. E.g. Toluene: PVC – soluble, ABS – insoluble; Dimethylformamide: PVC – insoluble, ABS – soluble.

@Jan. What about testing with specific glues?

As far as I know, there are several principles how glues working. E.g. if glue contains solvent I mentioned above, it will works because the principle will be the same. However, glues usually contain mixture of solvents. And, especially for glues working on different principles, surface properties (which can be/are influenced by other compounds in plastics, e.g. fillers, softeners (especially for PVC), fire retardants, …) are more important and may interfere with your glue-technique. This point is valid for all techniques mentioned above as IR, burning test, solubility test, density measurements, thermal analysis, …

PVC is denser than ABS. Just immerse a piece of the plastic in a glass containing a solution of 2 tablespoons of salt in 8 ounces of water. If it stays on the bottom it is PVC. If it floats it is ABS.

Very simple. Thank you.

For non anglo-saxon readers. 8 ounces = 226.8 g. 8 ounces = 1 cup = 250 ml.

Hi Gyorgi!

That flame test sounds potentially really useful for people who want to laser-cut plastic, but need to make sure that the plastic doesn't contain chlorine (in case it produces HCl, damaging the laser optics).

Do you happen to know if it's fairly foolproof for identifying other chlorine-containing plastics?

Pls find attached a short review of chlorine detection:

http://www.dexsil.com/uploads/docs/dtr_1305.pdf

it says that the Bielstein test is applicable only if chorine is present in % amount but not at the ppm level

Nobody proposed a proposal based on smelling ?

To characterize an unknown material, I always try this useful chart by Loy research group. I attached it here but you can also find it on their website. Hope it helps

@Ebrahim. Really great it answers largly beyond the question. Thank you very much.

I wish you a pleasant new year 2014.

@Charles, wish you a great Year full of success and happiness.