REGENERATION OF CELLULOSE FROM IONIC LIQUID SOLUTION: A NOVEL VALORIZATION ROUTE FOR FULL POTENTIAL UTILIZATION OF CELLULOSE

Cellulose as the most abundant natural polymer holds great potential as a raw material for the preparation of both sustainable and economically viable polymeric products hitherto predominantly produced from synthetic fossil-based polymers. However, the utilization of cellulose to its full potential is constrained by its recalcitrance to chemical processing. Prior to processing and conversion into valuable products, cellulose needs to be dissolved and then regenerated via an efficient, energy-saving, and environmentally benign route. In the late 1990s, ionic liquids (ILs)have been re-discovered as the most promising cellulose solvents. The application of these novel, green solvents is discussed in detail. The subsequent regeneration of cellulose solutions from these solvents into various products such as fibers, films, membranes, beads, aerogels, hydrogels, and composites including all-cellulose composites, as well as their application in biomedicine, sorption, agriculture, packaging, and thermal insulation, have been reviewed. The properties of the regenerated cellulose material can be additionally tuned by the proper choice of the experimental conditions such as temperature and polarity of the coagulation medium. Furthermore, recycling and converting waste paper and cardboard into high-value materials have been discussed. The recyclability of ILs is one of the challenges to making the process cost-effective and environmentally benignthat scientists and technologists dealing with cellulose processing need to solve.Celuloza kao najzastupljeniji prirodni polimer ima veliki potencijal kao sirovina za proizvodnju kako održivih tako i ekonomski isplativih polimernih proizvoda koji su se do sada pretežno proizvodili od sintetičkih polimera na bazi petrohemijskih sirovina. Međutim, korišćenje celuloze u njenom punom potencijalu je ograničeno njenom otpornošću na hemijske tretmane. Pre obrade i konverzije u vredne proizvode, celulozu treba rastvoriti, a zatim regenerisati efikasnim, energetski štedljivim i ekološki benignim putem. Krajem 1990-ih, jonske tečnosti (ILs) su ponovo otkrivene kao najperspektivniji rastvarači celuloze. U radu je detaljno razmatrana primena ovih novih, zelenih rastvarača, kao i regeneracija celuloze rastvorene u jonskim tečnostima u različite proizvode kao što su vlakna, filmovi, membrane, sfere, aerogelovi, hidrogelovi i kompoziti, uključujući i kompozite celuloza-celuloza, i primena ovih proizvoda u biomedicini, poljoprivredi, kao sorbenata, ambalažnih i termoizolacionih materijala i sl. Svojstva regenerisanih celuloznih materijala mogu se dodatno podesiti pravilnim izborom eksperimentalnih uslova procesa regeneracije kao što su temperatura i polaritet medijuma za koagulaciju. Nadalje, analizirana je mogućnost recikliranja i pretvaranja starog papira i kartona u materijale visoke vrednosti. Reciklabilnost ILs je jedan od izazova koji naučnici i tehnolozi koji se bave preradom celuloze moraju da reše kako bi se proces učinio isplativim i ekološki benignim