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The brittleness of ethyl cellulose (EC) film limited its full applications, and the addition of plasticizers is one of the most common methods to reduce its brittleness. However, the mechanical properties are normally dropped with the addition of plasticizers. Herein, cellulose nanocrystal (CNC) was chosen as a reinforcing agent to improve its mechanical properties. CNC was firstly extracted from the tobacco-stem and then modified by epoxidized soybean oil (ESO) via ring-opening grafting to obtain epoxidized soybean oil grafting CNC (ECNC). The grafting effect was evaluated by FTIR and XPS. After that, the films of ECNC/EC nanocomposites were prepared by the solution-casting method, and their mechanical, thermal and optical properties and fracture morphology were investigated. The results showed that at 4 phr loading of ECNC, the tensile strength of the nanocomposite film was up to 43.7 Mpa (about twice as much as that of the EC film plasticized by ESO), and the elongation at break was not influenced. Moreover, a higher thermal decomposition temperature was achieved for the ECNC/EC films. Besides, owing to the good dispersion, ECNC had no significant impact on the transparency, and the films presented high light transmittance in the visible light region.

It is well known that molecular structure has great influence on the porous structure prepared by breath figures. However, the effect of graft architecture on porous structure from graft copolymer is unclear. Here, the cellulose-based graft copolymers with different graft architectures were synthesized and the highly ordered porous films were facilely prepared by breath figure method. The effects of graft architecture with four different structural parameters on porous structure were systematically investigated. It was found that the pore size increased with the increasing graft chain length, main chain length or molecular weight, while the pore size decreased with the increasing graft density under other similar structural parameters. The shorter main chain and the higher graft density resulted in the smaller pore size. Moreover, the shorter main chain was more beneficial for the formation of highly ordered porous structure than the longer main chain. These results will help to understand the effect of graft architecture on porous structure and regulate pore size by adjusting the graft architecture.