Facile Preparation of Functional Cellulose Nanospheres from Nitrocellulose and Their Utilization for Poly(<i>n</i>-butyl acrylate) Enhancement

As a class of nanocellulose, cellulose nanospheres (CNSs) attract increasing attention due to their unique spherical morphology with larger surface areas, and the development of functional CNS from industrial cellulose derivatives is very promising for their resourceful utilization. In this work, nitrocellulose (abbreviated as NC) was used as a raw material to prepare functional CNSs with tunable sizes via facile denitration, followed by ultrasonication in an aqueous system. The reaction conditions of NC denitration were optimized by orthogonal experiments, and four CNS samples with different degrees of nitration (DoNs) were obtained by changing the NaHS concentration for denitration. The generated CNS samples were featured with a cellulose II-like structure, and their sphere sizes as well as crystallinity indices increased with a decrease in the DoN. One CNS sample with the most residual nitro groups (CNS-0.8) in this study demonstrates excellent strengthening and toughening effects to the poly(n-butyl acrylate) (PBA) matrix at a dosage of only 2 wt % owing to its good dispersity and compatibility in PBA. This presentation not only proposes a simple and green strategy to fabricate functional CNSs compatible with some hydrophobic polymer matrixes but also provides a feasible solution for the resourceful utilization of NC.