I have FTIR spectra of hydroxy-terminated PDMS and a tri-functional siloxane, which is a ketoxime type of cross-linker. There is a confusing peak at around 910cm-1, which is very strong in the spectrum of the silane cross-linker. You can have a look at the peak in the attached file.
I have searched through the literature and can see that this peak can be allocated to the Si-O stretching of SiOH(840cm-1 - 960cm-1). It means my tri-silane(the cross-linker) may be hydrolised and show an absorption band here. However, there is no peak at 910cm-1 in the spectrum of PDMS-OH, which should have this absorption even stronger than that of the X-linker. The hydroxy PDMS just have a peak at 888cm-1 and showed nothing in the range around 910cm-1.
Thus, the peak at 910cm-1 is mainly from the tri-ketoxime silane.
One of the literature stated that oxime , R-C=N-OH, can show a peak at 930-960 for stretching of N-O of =N-OH. In this case, the ketoxime silane, R-C=N-O-, has no Hydrogen bonding which can decrease the frequency of the absorption peak of N-O stretching (lower energy required to create the vibration). I do not know if my though is correct or not. If this is possible, then I can explain what happened there with my sample.
Please have a look at the attached file and let me know your though.
Your tri-ketoxime silane is a polymer? There is no in its FTIR spectra a peak at 3700-3400 cm-1 for stretching of O-H (if it is monomer with -C=N-OH groups)!
A siloxane from monomer with -C=N-OH groups contains -C=N-O-Si- groups, they can have a peak at 920 cm-1 (lower, than for -C=N-OH, because of Si instead H).
Tks Elena for your comment. I have the same thought like you.The normal oxime band is at 930-960, but my chemical here is -C=N-O-Si- instead of -C=N-OH, so it may require less energy for vibration.
The tri-ketoxime silane is not a polymer.
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