Cellulose Aerogels Based on a Green NaOH/PEG Solution: Preparation, Characterization and Influence of Molecular Weight of PEG

A green cost-effective NaOH/polyethylene glycol (PEG) aqueous solution was adopted to fabricate nanoporous cellulose aerogels, and three kinds of PEG with different molecular weights (200, 4000, and 20000) was carried out to investigate the effect of PEG molecular weights on the morphology, specific surface area and pore structure, crystal structure, and thermal stability of the resulting aerogels. The results show that the PEG with the higher molecular weight promotes the dissolution of cellulose, the formation of pore structure, and the transformation of crystal structure from cellulose I to cellulose II. After being modified by methyltrichlorosilane (MTCS), the aerogels are hydrophobic, and exhibit the oil adsorption ratios of approximately 13-18 g/g, much higher than those of the untreated cellulose aerogels (10-15 g/g). Besides, the oil adsorption ratio has a positive correlation with the pore characteristic parameters (specific surface area and pore volume), revealing the facile controllability.