Have you tried local universities.
Have you tried mailing samples to off shore universities.
Have you asked PE resin suppliers to test it for you.
Are you sure it is single layer.
If it is single layer, a simple density test and melting point test and MFI test should reveal all. These are very simple tests with very simple equipment.
If it is multilayer, you will need to test each layer. That will require fancy microscopes and equipment for measuring crystallinity.
Regards
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