Biocompatibility and adsorption properties of hydrogels obtained by graft polymerization of acrylic acid on cellulose from rice hulls

Hydrogels constitute a group of cross-linked polymeric materials with the capability of swelling and retaining large amounts of water without dissolving. In this work, the hydrogels were obtained by grafting the acrylic acid on cellulose from rice hulls and cross-linking it with glycerol, ethylene glycol, and polyethylene glycol ( M w = 200 and 10,000 g mol −1 ). The samples were characterized using IR and Raman spectroscopy, the absence of the bands at 1636 and 1614 cm −1 (in IR) and at 1659 and 1637 cm −1 (in Raman), in the spectra of grafted cellulose and assigned to ν(C=C), indicated the polymerization process and the absence of the monomer residual. The cross-linking process was verified by the appearance of bands at 1090 cm −1 (IR) and 996 cm −1 (Raman), attributed to ν(C–O–C). Thermogravimetric analysis showed that the cross-linked sample with glycerol presented the lowest thermal stability. The molecular mass of CDClCC- g -AA was 55.56 ± 5.21 kDa with an R 2 of 0.9741 and the CDClCC average particle size of 694 nm. The topography and the average roughness of the samples were obtained by atomic force microscopy and the samples that were cross-linked with the polyethylene glycol presented greater roughness. The degree of swelling was lower in the sample cross-linked with ethylene glycol, which was related to its higher degree of cross-linking. Finally, the biocompatibility of the samples was studied by analyzing the toxic effect of the samples on human embryonic kidney cells, where results showed that samples cross-linked with ethylene glycol were non-toxic.