FT-IR measurement as a simple tool for following formation of acidic functional groups in maleic anhydride containing polymers

Abstract

Titration is a measurement for maleic-anhydride containing polymers with significant chemicals consumption, time and human resource requirement meanwhile all the carbonyl groups have to be supposed to be in the cyclic form but it is not always the situation. Core of the FT-IR method has been determination of carbonyl groups in various chemical environments. The FT-IR method is developed to obtain more precise and prompt results about anhydride rings in the copolymer chain than with titration in the whole coupling number range with minimal chemicals consumption. Quantitatively apprising FT-IR results peaks of carbonyl groups have been considered since those yield well-isolated and high intensity peaks in the spectrum. Two distinct methods have been adopted for integration of areas under the selected stretching vibrations. Not all the anhydrides have been supposed to be in ring form in the copolymers but partially in acidic form that can be only taken into account by double counting during titration instead of the correctly single counting. FT-IR spectrum has been feasible for tracing that progress but titration isn't.Moreover, if difference between acid number from titration and FT-IR methods based on the chemical structure is high compatibilizing additive synthesis requires excess of reagents.•A method enabling the identification of carbonyl groups in maleic-anhydride containing polymers in various chemical environment without chemical consumption.•The method is based on the calculation of functional group ratios applying the integrated area of selected absorption peaks.