Dear Attila Toth, because they are not compatible. They are different in many aspects. PP is apolar and polyamides polar. If they are to be recycled together, a third component should be added,i.e., a compatibilizer. My Regards

Abdelkader BOUAZIZ is absolutely right.

You also can try to find info in patents - nowadays, polymer manufacturer pays lots of attention to plastic recycling.

As an example: WO201721389.

Hope, you can find more here:

patents.google.com

www.epo.org

Dear Attila,

In order to achieve a good recyclate the polymers should be possibly

- close in chemical composition

- close in melting points (in the case of semcrystalline polymers)

- close in rheological properties.

If the polymers are dissimilar (as PP and PA) even if both polymers are molten, they will not mix with each other, remain phase separated and the rsultin polymer mixture will have a very small elongation at break. To improve the porperties you have to use compatilizing agents (in this case e.g. so-called tie-layer resins) to improve the compatbility.

If the melting points are very far from earch other (as in the case of PP and PA) one of the componets will melt much earlier, causing problems.

PA show usually ver ylow viscosity above the melting point, while PP changes viscosity gradually.

The essential problem in the formation of PP/PA blends is immiscibility, because of the difference in chemical structure of both components.

The cited polymers will not mix to each other because they are not compatible

Actually, Nylon 6 and PP can be reclaimed together. However a lot of constraints must be complied. It´s not a straight answer.

Dear Attila,

In fact, even that PP is not miscible with polyamides as already mentioned by other RG colleagues, and as it comes out from the from literature, please consider that the blends between polyolefins and polyamides are doing the subject of many studies, whereas some products are/have been industrially commercialized.

I would like to recommend you to consider for more information the book “Commercial Polymer Blends” (Author. L.A. Utracki, 1998 Publisher Springer, DOI 10.1007/978-1-4615-5789-0).

In the chapter “Polypropylene” you will find that the first modern PA/PP blends were produced using as compatibilizer PP functionalized with maleic anhydride. However, nowadays are commercialized some polyolefins/polyamide blends, while the literature is very rich with this subject.

In this context, I assume that the recycling of blends of polyamides and PP is practically feasible, but not very easy as technology, due to different factors that must be considered in such processes.

Good luck in your R&D study,

Marius

Hi Attila,

I have a very different answer, when you say recycle what recycle technique you are talking about? I don't think miscibility is going to affect the recycle. You only need to see if the process can be able to handle these two polymers, if the process is able to handle them individually it will definitely handle the mixture too. Technique such as pyrolysis is capable of handling such polymer mixture and in fact presence of PP can promote the recycling of PA.