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Chitosan-based membranes with different ionic crosslinking density for pharmaceutical and industrial applications

Gierszewska, Magdalena, Ostrowska-Czubenko, Jadwiga
Carbohydrate polymers 2016 v.153 pp. 501-511
Fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy, chitosan, contact angle, crosslinking, differential scanning calorimetry, energy-dispersive X-ray analysis, freezing, hydrophilicity, industrial applications, molecular weight, pH, roughness, temperature, tripolyphosphates
Chitosan membranes (Ch), ionically crosslinked with pentasodium tripolyphosphate (TPP), were prepared using chitosan of medium and high molecular weight of similar degree of deacetylation and different crosslinking conditions. An effect of synthesis conditions (pH of crosslinking TPP solution equal to 5.5 and 9.0) on molecular and supermolecular structure and on crosslinking density of Ch/TPP membranes was confirmed using Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD) method and energy dispersive X-ray (EDX) spectrometry. Atomic-force microscopy (AFM) and contact angle measurements indicated some differences in membrane roughness and hydrophilicity. The state of water in non-crosslinked and ionically crosslinked Ch membranes containing different amount of water was investigated by low temperature differential scanning calorimetry (DSC) measurements. DSC analysis confirmed presence of freezing and non-freezing water in non-crosslinked and ionically crosslinked membranes. The amount of non-freezing water generally decreased after Ch crosslinking and was affected by crosslinking conditions and crosslinking density. Molecular weight of Ch had only slight influence on all characterized properties of ionically crosslinked membranes.