Synthesis, characterization, and gas permeabilities of cellulose derivatives containing adamantane groups.

Cellulose derivatives containing adamantane groups are homogeneously synthesized by a simple, rapid and environmentally friendly way using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as reaction media. Without any catalysts, cellulose adamantates (CAd) with degree of substitution (DS) in a range from 0.71 to 2.25 are prepared just in one-step. In addition, a series of mixed esters, cellulose adamantate acetate (CAdAc), are also synthesized via the “one-pot” process. The obtained CAd and CAdAc are characterized by means of FT-IR, NMR, XRD, DSC and TGA. Meanwhile, their gas permeabilities of these materials for O 2 , N 2 , CH 4 , CO and CO 2 are studied. CAd exhibits improved solubility in organic solvents, low glass transition temperature and good thermostability. In particular, the free-volume topology of CAd membranes has been tailored by controlling the DS of adamantane, thus CAd membranes display a significant enhancement for gas permeability with good ideal permselectivity for several gas pairs, such as O 2 /N 2 , CO 2 /N 2 , CO 2 /CH 4 and CO 2 /CO. For CAdAc, introducing only a small amount of adamantane groups in cellulose acetate could achieve better gas permeability and similar or slightly lower ideal permselectivity. [ABSTRACT FROM AUTHOR]