I have to find carboxyl acids quantitatively via basic calculation except any experimental study such as titration etc. How can I calculate the amount of carboxylic acid groups in polymer chains?
Your question is so vague. Surely you don't mean --'Without an actual Experiment' ! Or, do you mean 'How might I estimate the hypothetical number of free carboxylic acid groups on a polymer?' Then, if it that simplistic, just multiply the free groups by the number of monomers. Otherwise please rephrase the question - stating the polymer in question.
covert acid to esters and analyzed on 1H-NMR to know the number of protons of methyl group.
I try to explain it with an example. If you make a copolymer (quantitative yield assumed) of 37g (0.5 mol) acrylic acid and 163 non-functional monomers (styrene, acrylates, methacrylate) you result in 200g of a polymer containing 0.5 equivalents of acid groups, that means that the equivalent weight in relation to acid groups is 400 g/eq. From this you can calculate the acid number. 56100/eq-weight=acid number, that means 140.25 in our case. If you know, e.g. determined by GPC, the molecular weight of your polymer, e.g. Mn = 10000 g/mol, you can calculate your functionality: 10000/400=25, that means that every chain has in average 25 acid groups.
So I have to ask another one to clear my research what Im going to perform. Do you have any article to recommend about EDC/NHS coupling reaction on PLLA polymer cause I'd generally found copolymer structure?
Dear all thank you for answers. I can calculate in basic for PLLA but on the other way for fibroin (have extracted polymer) guess I have to convert acid to ester and determine value of carboxylic acids via NMR. So depends on polymer as John George said thank you again.
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