How to identify the grade/type of plastic

[Ian63]

What is the best way to determine the grade of plastic used on a particular injection moulded part?

If it were steel I would have it spectro-analysed, but I don't know if there is a way to do this to plastic.

I have seen the charts with the smoke characteristics when burned, but these don't seem to tell you more than say it's polypropylene or polyethylene for instance.

thanks for any assistance anyone can offer.

 

[patprimmer]

Your problem is not so easy as there are no Std grades.

The smoke test, combined with flame colour and nature of flame easily identifies most, but not all polymer types. Alloys and heavily modified materials add confusion to this.

You can also test for density, hardness and melt flow index.

Testing for colours, stabilisers, lubricants and flame retardants is much more difficult. IR spectrophotometry is a useful tool if the polymer is uncoloured.

Regards

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