solvent for HDPE

[clandestinho]

Hi

does anybody know a good solvent for HDPE other than xylene?

I need to solution impregnate a woven fabric with HDPE and I am after a solvent which is less harmful to health and environment and if possible with a lower boiling point.

any ideas?

Thanks!

 

[patprimmer]

I was not aware of anything including Xylene that truly dissolves PE.

Back when I did fibre analysis for fibres in mixture, we used all sorts of solvents to remove certain fibres, including Formic acid for nylons and boiling 90% phenol for PET. I never found a way to remove PE or PP and presumed anything left was one of those. This was then confirmed with a melting point test and was the only way short of IR to test for PE in a yarn or fabric.

Regards
Pat
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[clandestinho]

Hi Pat,
thanks for your reply and I agree that PE is a difficult one. I have found academic R&D indicating that xylene will dissolve low density PE at temperatures around 70C / 160F but I haven't tried this myself. I assume that xylene will work on HDPE as well.

did you try xylene for PE or PP by any chance? Perhaps at higher temperatures?


Regards,
Claus

 

[patprimmer]

It was 1970 or thereabouts, so I don't really recall all solvents tried. I do remember PE was classified as not soluble in anything.

HDPE will be more difficult than LDPE due to the increased strength of the bonds due to higher crystallinity. Also of course the reason behind the higher melting point of HDPE.

Regards
Pat
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[unclesyd]

It can be done and is done in a large scale facility. We did a lot of research at much higher temperature and pressure. I don't know what you are trying to accomplish but our work took different turns as the M.W. got higher
The first link is to information on Polywas and some discussion about solvents, all bad. The second link is to method for recovering various plastics.
The third link is to information on P.E. dispersions that you might want to look into.

http://www.yinsen.net/file/wax/datasheet/Polywax.pdf

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1469979/pdf/envhper00317-0038-color.pdf

http://www.crayvallac.com/products.html

patprimer,
If you ever have to clean up P.E. residue you need to get a Pyrolysis Oven which can een clean glassware.

 

[clandestinho]

Unclesyd,

thanks for taking time to advice on this. It was very interesting reading about the recycling method - which also confirms that xylene is a solvent for HDPE although at even higher temperatures.

recyclability is one of several reasons that I am now looking at thermoplastics to replace some thermoset coating or impregnation resins used for textiles.

I need to test different impregnation methods against each other, one is a solvent borne dispersion, another involves a solution of 10-20 wt% of PE in a heated solvent such as xylene.

I might even have used the PE solution from that recycling plant but I guess the M.W. distribution will be too wide. I have a narrow temp window for heat consolidation.

I guess I wil use xylene for my tests, this seems to be a well proven solvent.

Also thanks for the 2 other links, although I'm not sure I understand what "wax" in Polywax refers to. They are referred to as linear, highly crystalline saturated PE homopolymers. That tells me they should be pellets or powder. yet they cal them waxes. what am I overlooking here?


regards,
Claus

 

[patprimmer]

In the alkane series molecular weight differentiates between gas, liquid, grease or jell, wax and plastic solid. Degree of side branching of the main backbone also has some influence.

Regards
Pat
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[Compositepro]

Waxes (e.g., paraffin)are essentially low molecular weight polymers.

 

[unclesyd]

I don't understand the chemistry of all the derivatives of polyethylene. I have used all all of them in one form or another. The first two are for Polyox and Carbowax from Dow. The third is a link to a producer of polyethylene fabric.
The fourth link is to a patent that combines Nylon and Polyethylene. I don't recall working on this project which is one many projects to combine Nylon.

http://www.dow.com/inspecpolymers/prod/polyox.htm

http://www.dow.com/polyglycols/carbowax/products/mpeg.htm

http://www.fabrene.com/profile.html

http://www.freepatentsonline.com/5913993.html

You concern about nasty solvents some Non-Woven Nylons are bonded using HCl sand temperature. A process I developed for cleaning Nylon Polymerization Equipment using molten Adipic Acid. This not very nice stuff but fortunately when we add the Adpic to the process it is enclosed.

 

[Demon3]

GPC is done on various PE types so solvents do exist. They are nasty and high temperatures are needed. I'd give up on that idea.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry