Structure-Property Relationships in 5-Aminosalicylic Acid-Functionalized Poly(GMA-co-EGDMA) Microspheres: Porosity,...

Porous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres with tunable functionality were synthesized via suspension-emulsion polymerization and subsequently modified with 5-aminosalicylic acid (ASA). The influence of copolymer composition (GMA:EGDMA = 1:1-5:1) on porosity, surface chemistry, and thermal properties was systematically investigated. Increasing the GMA content led to higher epoxy group density (2.87-5.02 mmol g^-1) but a pronounced decrease in specific surface area (151-39 m²g^-1), indicating a trade-off between functionality and porosity. Post-polymerization modification successfully introduced ASA moieties, as confirmed by FTIR spectroscopy and acid number measurements (14.0-30.9 mg KOH g^-1), while largely preserving the mesoporous structure. Thermal analysis (TG/DTG and TG-FTIR) demonstrated enhanced thermal stability of ASA-modified copolymers, attributed to the incorporation of aromatic functionalities and reduced content of thermally labile epoxy groups. The modified materials were evaluated as sorbents for Cr(VI) ions, showing strong pH-dependent behavior with maximum removal efficiency under acidic conditions. The sorption capacity reached approximately 100 mg g^-1, and the uptake mechanism was governed by electrostatic interactions between protonated surface groups and anionic chromium species. These results demonstrate that ASA-functionalized poly(GMA-co-EGDMA) microspheres are promising materials for selective sorption applications.