Chitosan-xanthan gum PEC-based aerogels: A chemically stable PEC in scCO2

• Autor(a) principal: Tomé, Luciana I. N.
• Data de Publicação: 2022
• Outros Autores: Reis, Marco S., Sousa, Hermínio C. de, Braga, Mara E. M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/100802; https://doi.org/10.1016/j.matchemphys.2022.126294
• topic: Polyelectrolyte complexes; Aerogels; DOE; Supercritical-drying; Xanthan gum; Chitosan

An innovative aerogel obtained from a chitosan/xanthan gum polyelectrolyte complex (PEC) was developed in this work from the screening of thirteen different combinations of natural polyelectrolytes: two positively charged biopolymers (chitosan and gelatin A), six negatively-charged biopolymers (pectin, iota-carrageenan, collagen, xanthan gum, alginate and modified galactomannan), and a neutral polymer (guar gum) using the statistical design of experiments (DOE) approach. Only the chitosan-xanthan gum formed aerogels under supercritical conditions using carbon dioxide at 150 bar and 250 bar and 35 ◦C. The chitosan-xanthan gum-based aerogels have bone-like structures and smooth surfaces, with pore size distributions in the meso- and macropore ranges, the average pore diameter of ~20 nm and porosity between 60 and 70%. The specific surface areas of the aerogels processed at 150 bar and 250 bar are, respectively, 5.7 and 17.5 m2 g− 1, values below those commonly reported in the literature for aerogels. The aerogels are thermally stable up to ~240 ◦C, while the cryogel is thermally stable up to ~224 ◦C. The value of the total weight loss through thermal decomposition of the aerogels (~25%) is smaller than that of the cryogel (~40%). These materials have potential applications in the environmental and biomedical areas, providing solutions to the current challenges in biomedicine and social, demographic and sanitary life sciences.