Nanofibrillar cellulose aerogels have been reported, it can be prepared by the dissolution of cellulose in hot aqueous calcium thiocyanate, and aqueous solutions of NaOH or LiOH and urea respectively. Recently, we found that lithium chloride/dimethyl sulfoxide (LiCl/DMSO) can dissolve ethylenediamine (EDA) pretreatment unbleached kraft pulp with high lignin content.Various cellulose samples, such as microcrystalline cellulose (Whatman CF11), filter paper pulp (FPP), and bleached sulfite pulp (BSP) were completely dissolved in LiCl/DMSO after a pretreatment with EDA. Cellulose hydrogels and aerogels were prepared by dissolution of cellulose in 8% LiCl/DMSO solvent system. These aerogels had highly porous networks consisting of fibrils about 20 nm on the middle part. Cellulose dissolved in 8% LiCl/DMSO via EDA pretreatment was found to undergo reaction with tetraethyl orthosilicate (TEOS) at room temperature, forming transparent gels. This phenomenon apparently showed the TEOS undergo ester exchange with cellulose, and the multivalency of TEOS gave rise to crosslinking of dissolved cellulose. Several aspects of behavior of this system were consistent with this interpretation. The presence of trace EDA, arising from cellulose pretreatment, was essential for the reaction, probably acting as catalyst. Cellulose-silicate composite aerogels were prepared from these transparent gels after solvent exchange with ethanol followed by tert-butanol and freeze-drying. The aerogels were investigated by SEM, EDX and BET analysis.<br/><b>Acknowledgements</b><br/>This research was supported by the National Forestry Public Welfare Industry Research Project (201304609), the National Natural Science Foundation of China (31200444), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (12KJA220001).

Preparation of nanofibrillar cellulose-silicate composite aerogels by LiCl/DMSO cellulose solution

251st National Meeting (2016)

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