Influence of lignin on cellulose-NaOH-water mixtures properties and on Aerocellulose morphology

Microcrystalline cellulose and organosolv lignin, both dissolved in 8%NaOH-water, were mixed with the objective to study the influence of lignin on the properties of cellulose solutions and on the morphology of dry porous materials. Mixture viscosity and gelation were investigated. Cellulose-lignin gels were regenerated in aqueous acid baths and dried under supercritical CO2 to obtain Aerocellulose, an aerogel-like material. The presence of lignin in the mixture speeded up gelation. During regeneration part of lignin was washed out. This created large pores and channels in the dry materials. The overall results obtained showed that cellulose and lignin are not compatible in the solvent used.