Microwave-assisted hydrolysis for the physicochemical characterization of functional methacrylic polymers and their bioconjugates

Abstract

This study presents a microwave-assisted hydrolysis (MAH) method for accurately determining the molar mass of functional methacrylic polymers and their protein conjugates synthesized via controlled/living polymerization by a grafting from approach. By cleaving ester side chains, MAH converts polymers into linear poly(methacrylic acid) (PMAA), enabling precise molar mass analysis through aqueous size-exclusion chromatography (ASEC). The method is applied to polyglycerol methacrylate (PGMA), polyethylene glycol methacrylate (P(PEGMA)), and lysozyme–PGMA conjugates, with hydrolysis kinetics evaluated under both conventional and microwave heating. Notably, P(PEGMA) exhibits strong resistance to base-catalyzed hydrolysis due to PEG stabilization; however, microwave irradiation significantly improves conversion, achieving results infeasible with standard heating. Characterization by ¹H-NMR, FTIR, and SEC confirms successful hydrolysis and accurate molar mass determination. Calibration using PGMA standards further enhances analytical reliability. The MAH–ASEC approach proves robust, scalable, and broadly applicable, offering a valuable tool for the physicochemical characterization of complex polymeric conjugate systems, particularly in biomedical and materials science contexts.