Hello,
I am working on the photocatalytic degradation of PEG 400. I would like to know if it's possible to determine the degree on polymerization based on NMR integration, or by the MW of the polymer?
I did a quick search and found this page: https://www.sigmaaldrich.com/materials-science/polymer-science/polymer-analysis.html . However, I am not able to locate the end group proton signals due to proton exchange.
Attached is the NMR spectrum of PEG 400 at 0h. I used an internal standard (1,1,2,2-tetrachloroethane) - it's to facilitate the calculation of the yield of the reaction. I'm guessing that the stronger (more intense) signal is from the repeating units, whereas the weaker signal (around 3.4ppm) corresponds to the protons at the tail end of the polymer.
Thank you.
Dear Ht Liang, please check this similar RG thread and the references therein. My Regards
https://www.researchgate.net/post/How_to_calculate_the_molecular_weight_of_PEG_from_proton_NMR
Dear Ht Liang, please check this similar RG thread and the references therein. My Regards
https://www.researchgate.net/post/How_to_calculate_the_molecular_weight_of_PEG_from_proton_NMR
You might convert the alcoholic endgroups into esters. This will
shift the proton signal of the CH2-O endgroup of your polymer to
approx. 4.2 ppm. Non proton containing anhydrids like Trifluoroacetic
anhydride should allow derivatisation in the nmrtube.
Intensities of endgroup and chain signals will allow the calculation of the
chainlength.
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