The Preparation of Enantiopure [6]- and [7]Helicenes from Binaphthanol

Abstract:Based on a NaOH/urea aqueous system, a facile and convenient method was proposed to prepare graphene oxide/cellulose composite films with superior mechanical performances and excellent ultraviolet-shielding properties. Unexpectedly, it is found that more uniform dispersion of graphene oxide (GO) in a cellulose/NaOH/urea aqueous solution could be realized by mixing them at low temperature rather than room temperature. Epichlorohydrin (ECH) was introduced as a cross-linking agent to enhance the performance of GO/cellulose composite films. With the synergistic effect of chemical cross-linking and the strong hydrogen bonding interaction between GO and the cellulose matrix, the tensile strength, elongation at break and fracture energy of the thus prepared composite film with 0.5 wt% GO loading were significantly improved by 78%, 172% and 397%, respectively, compared with the pure cellulose film. Moreover, it is found that the cross-linked GO/cellulose composite film also possessed excellent ultraviolet-shielding properties. These enhanced properties indicate that the cellulose based composite material has great potential for use as a high performance bioplastic film.

Volume:6

Issue:77

Translation or Not:no