Facile preparation of biocompatible macroporous chitosan hydrogel by hydrothermal reaction of a mixture of chitosan-succinic acid-urea

Publication date: November 2019Source: Materials Science and Engineering: C, Volume 104Author(s): Prabha Govindaraj, Narayanan Abathodharanan, Kartik Ravishankar, Dhamodharan RaghavachariAbstractThe facile preparation of macroporous, super water absorbing, biocompatible hydrogels of chitosan involving the hydrothermal reaction of a mixture of chitosan (CH), succinic acid (SA) and urea (UR), all of which are sustainable materials, is reported. The structure of the dry CHSAUR was ascertained by CP MAS-SS NMR spectroscopy, Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction analysis (PXRD), and thermogravimetric analysis (TGA). The principle role of UR in the synthesis was identified as the source of ammonia, which increased the pH of the acidic chitosan solution with reaction time, leading to the formation of the insoluble hydrogel of chitosan accompanied by the formation of pores of different sizes and volumes. In addition, a small fraction of urea participated in chemical reaction with the primary hydroxyl groups in the sixth position of the glucosamine repeat units of chitosan resulting in carbamate linkages. The as-prepared hydrogel, following workup and methanol extraction, was found to be chitosan crosslinked with succinic acid through electrostatic interaction. It was macroporous with percentage porosity varying between 49.4% to 64.2%. It also exhibited different extents of water uptake with the maximum of 760 ± 20 g/g being for the one prepar...
Source: Materials Science and Engineering: C - Category: Materials Science Source Type: research