Cellulose dissolution and regeneration have had important applications for a long time, mainly for textile fibres and for the preparation of cellulose derivatives. Cellulose can be dissolved in water at extreme pHs, in particular if a cosolute of intermediate polarity is added. We argue that cellulose is significantly amphiphilic. Cellulose has a strong tendency to re-assemble when dissolved; this process is strongly affected by surfactants and other additives decreasing hydrophobic interactions. In this work we have explored cellulose dissolution under aqueous alkaline conditions with urea as a solution-promoting cosolute of intermediate polarity. We have considered the co-regeneration of cellulose with another polysaccharide to prepare novel renewable materials. The behaviour of cellulose and chitosan polymer solutions and their mixtures was studied by rheology measurements. The dynamic rheology and the influence of time and temperature on the gelation of cellulose-chitosan solutions mixed at different ratios were investigated. Cellulose-chitosan nanocomposite particles and films were successfully prepared for the first time. Via mixing of the biopolymer solutions, emulsification (w/o) and regeneration by temperature induced sol-gel transition followed by addition of an antisolvent, spherical microparticles were obtained. Films were cast and regenerated. Using tuned protocols, different particle sizes, biopolymer distribution, porosity and mechanical performance could be obtained. Furthermore, a facile one-pot synthesis of spherical polycrystalline copper nanoparticles templated by regenerated cellulose in aqueous alkaline solution was demonstrated. The antibacterial properties were investigated for all the novel cellulose materials prepared.

Water-based dissolution of wood cellulose and design of novel cellulose-based nanocomposite materials

253rd National Meeting (2017)

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