Hi
Greeting!
I have developed pH and thermosensitive (P(Nipam-co-AAc) and characteristic for 1H-NMR. The H-NMR confirmed the copolymer formation.
However, I want to find out the copolymer compostion. In couple of the article that I have refereed, author has determined copolymer composition comparing the peak area of the NIPAAm C-H signal at 3.9 ppm with the total peak area between 0.7 and 2.2 ppm (encompassing the remainder of C-H protons)of HNMR data (Please find the attachment). However the author didn't presented HNMR spectra.
Can anyone say me wht do author mean by encompassing the remainder of CH proton?
I am attaching the following article and my results. Can anyone help me to this?
The Formulation code PNA0 to PNA 2 were prepared using different amount of NIPAM and AAc. Where PNA0 is homopolymer P(NIPAM).
Thank You
I got an impression that the incorporation of PAAc units is extremely low in your case with respect to the feed. Anyway you can also refer to these two papers,
1. http://pubs.rsc.org/en/Content/ArticleLanding/2014/TB/C3TB21519A#!divAbstract
2. http://pubs.rsc.org/en/Content/ArticleLanding/2014/TB/c3tb21360a#!divAbstract
What I observed is only the peak area under (NH) signal in your case is changed upon changing the composition.Also considering it as a mobile proton we can not directly take its integration into account. Also the peak of C-H protons from the polymer backbone attached to -COOH group which should be at 2.5 ppm in your case is very low. It is present there in your spectra (very low intensity) you can zoom it and try to make integration and correlate it with the -CH proton signal at 1.85-1.9 ppm and try to determine the composition.
I have attached my caculcation for you as reference. In your study, your prepare PNA1, PNA1.5, and PNA2. Becasue the amount of AAC change not significant in PNA1 PNA1.5 and PNA2, the exactly ratio of AAC/Nipaam is close. Why not prepare PNA1 PNA5 PNA10? And you will get more clearly difference.
I have attached my caculcation for you as reference. In your study, your prepare PNA1, PNA1.5, and PNA2. Becasue the amount of AAC change not significant in PNA1 PNA1.5 and PNA2, the exactly ratio of AAC/Nipaam is close. Why not prepare PNA1 PNA5 PNA10? And you will get more clearly difference.
I have attached my caculcation for you as reference. In your study, your prepare PNA1, PNA1.5, and PNA2. Becasue the amount of AAC change not significant in PNA1 PNA1.5 and PNA2, the exactly ratio of AAC/Nipaam is close. Why not prepare PNA1 PNA5 PNA10? And you will get more clearly difference.
When your measure NMR for COOH-functionalized polymers in D2O, there might be proton exchange, which gives you different results. You better use DMSO-d6 and picking the peak integral for comparison to get the ratio between PAA and PNIPAAm units for MW or composition results.
Thank you so much for this positive response. Your inputs were very very valuable for progress of my research. In response to Hsieh-Chih Tsai query, I have also prepared PNA 2.5, 5, 7.5, 10, 12.5 and 15. However based on the pH and Thermo-senstitive response, I moved ahead with the research towards focusing particularly on the above-said co-polymer composition. Once again I really appreciated your patience and valuable time given for helping me out. Thanks
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