[zgryzik]

Hello!

I am new here. I have a huge problem, on my university I received two FTIR charts I think they`re some sort of polyamides, but I am not sure at all.
Is there any possibility for you to help me figuring out what those materials are?


1.https://ibb.co/nHd1Aq
2.https://ibb.co/djFRbV

I have also the DSC chart
for the 1st https://ibb.co/btoRAq
for the second  https://ibb.co/c2QpVq

Thank you so much!

[mjc123]

You have to show an attempt at answering the question before receiving help, that's a forum rule. What do you think the spectra tell you?
Are these materials you have made yourself and got analysed, or are they some random spectra you were given as an exercise?

[zgryzik]

The FTIR should tell me what my material is. The DSC shows the two peaks instead of one. That probabelly means, that it`s some sort of copolymer, or the first peak is caused by the fiber glass.
I receive this material on my studies and I have to diagnoze what is that.
I also burnt my material in order to compare it to other. The fire test of my material match the Polyamid almost 100%, but it doesnt burn outside of the flame (the clear polyamide burns).
So I guess, there is a lot of fire retardant inside.

https://tinypic.pl/trdq6icfaq28


I also found characteristic absorbtions of the IR, but I am not sure, how to use it properly...

http://www2.ups.edu/faculty/hanson/Spectroscopy/IR/IRfrequencies.html

[mjc123]

You didn't say anything about fiberglass or fire retardant!
I think the first one is Nylon 6,6. (Google "Nylon 66 IR spectrum".) I'm not sure about the second, but 2299 suggests an isocyanate (not on your list!).

[zgryzik]

Do You see any other characteristic peak on the second material FTIR? C-O? N-O?

[zgryzik]

https://www.sciencedirect.com/science/article/pii/S0379711209000964?via%3Dihub

I found such article. Maybe my material is connected with the PBT, not PA as I thought?

[mjc123]

PBT looks a good shot. It would fit most of the ir peaks except 2300, and also the DSC melting peak.

[zgryzik]

What the 2300 peak might be? Cant find anything here :http://www2.ups.edu/faculty/hanson/Spectroscopy/IR/IRfrequencies.html

And the other  problem is : the melting point of PBT is about 220 while my material has 250. What might cause such difference? Glass fiber? Fire retardant?

[wildfyr]

You sure 2300cm-1 isn't O2 from the air? Happens when someone is breathing nearby as it's poorly backgrounded

[zgryzik]

Do You think so, Sir?

[mjc123]

O₂ in infrared?
Frequency is reported as 2061 (Raman).
Sample 2 melts at about 220°C. I'm thinking sample 1 is Nylon 6,6 and sample 2 is PBT. Or are you saying they are related (e.g. one is a precursor or decomposition product of the other)?

[wildfyr]

Oooooops I meant co2