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.
Dear Robert and Michael sorry for details was not included in question and couldn't back to here to answer for you. Thank you again.
- Badges
- Science topic