Testing for Ethylene Glycol Layer on PMMA Experiment

[dacruick]

Hi

I am doing an experiment right now trying to make a mould out of a poly methyl methacrylate (PMMA) using a resin containing Epichlorohydrin and ethylene oxide.

I do not know very much about chemistry but through some research I see that ethylene oxide can react with water to produce glycol. I also hear that PMMA can absorb water.

Is it possible that there was enough water absorbed into the PMMA that the ethylene oxide reacted with it and formed a layer of glycol at the top?

And my big question is, is there any easy way to test if the layer is ethylene glycol?

Thanks a bunch

dacruick

 

[chemisttree]

Ethylene glycol is soluble in water in all proportions. Epichlorohydrin is slightly soluble.

If you have a copper wire, pass it through a hot flame (blue flame from bunsen burner) and when cool, dip it into the liquid. Put that back into the flame and look for green. Green signifies chlorine and means that you have at least some epi in that sample. http://www.sha.org/research_resources/conservation_faqs/documents/beilstei.pdf"

 

[dacruick]

I will try that. But to clarify, I do not have any water (or at least no water that I meant to have), in the resin. It was simply the resin and the acrylic only.

originally I had the ethylene oxide and the epichlorohydrin, then I mixed in Triethylenetetramine which is the hardener for the resin. It has now completely cured and is a solid block of this resin, but with an oily substance on the top.

bubbles have formed of this oily substance and if I had to guess, I would guess it is glycol.

Thank you for your help, and in advance for any future help:).

Oh P.S

The bubbles are very small, I am concerned that I won't be able to scavenge enough of it to create a flame that is green.

 

[chemisttree]

Don't worry, it's a very sensitive test.

 

[LudusRex]

shank

Hello dacruickshank,

Thank you for sharing your experiment with us. It's great to see you taking an interest in chemistry and conducting your own experiments. Let me address your questions one by one.

Firstly, it is possible for ethylene oxide to react with water to produce glycol. This is known as the ethylene glycol hydrolysis reaction and is commonly used in the production of ethylene glycol. However, in your experiment, you are using a resin containing both epichlorohydrin and ethylene oxide, so it is unlikely that there will be a significant amount of ethylene oxide available to react with water and produce glycol. Additionally, PMMA is not known to readily absorb water, so it is unlikely that the ethylene oxide would react with any water present in the PMMA to form glycol.

To test for the presence of ethylene glycol, there are a few options you can consider. One simple method is to use a pH strip to test the pH of the layer. Ethylene glycol has a pH of around 7, so if the layer is acidic or basic, it is not likely to be ethylene glycol. Another method is to use gas chromatography-mass spectrometry (GC-MS) to analyze the composition of the layer. This technique can accurately identify the presence of ethylene glycol and other substances in the layer. However, this method may require specialized equipment and training.

In conclusion, it is unlikely that the layer on top of your PMMA is ethylene glycol. I suggest conducting some further tests to determine the composition of the layer. Good luck with your experiment!