For Mn>25000, too little solution volume is used for titration because there are very few terminal groups.
It is not possible to use a concentrated solution of these polymers due to the high viscosity of polymer solutions with Mn > 25000. This scenario is unsuitable.
Using highly diluted titrating agents; in this case, the titration curve is very flat and obtaining the equivalence point with an indicator is very challenging; even using an automatic titrator with the maximum sensitivity of the pH metre, it is possible to obtain very low repeatability. Likewise, using very diluted titration agents, polymers with moderately strong terminal groups, even those with Mn = 50000 uma, can be obtained with acceptable repeatability (e.g. HCl 0.01-0.02 N or NaOH 0.01 -0.02 N).
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