Robust and flexible cellulose sponges were prepared by dual-cross-linking cellulose nanofiber (CNF) with γ-glycidoxypropyltrimethoxysilane (GPTMS) and polydopamine (PDA) and used as carriers of metal nanoparticles (NPs), such as palladium (Pd). In situ growth of Pd NPs on the surface of CNF was achieved in the presence of polydopamine (PDA). The modified sponges were characterized with FT-IR, XRD, EDX, SEM, TEM, and TGA. XRD, EDX, and TEM results revealed that the Pd NPs were homogeneously dispersed on the surface of CNF with a narrow size distribution. The catalysts could be successfully applied to heterogeneous Suzuki and Heck cross-coupling reactions. Leaching of Pd was negligible and the catalysts could be conveniently separated from the products and reused.Keywords: catalysts; Cellulose nanofiber; palladium; polydopamine; sponge;

Thiol–ene click reaction was employed to synthesize a flexible hydrophilic cellulose sponge. The reactive vinyl group was introduced by silanization treatment with vinyl-trimethoxysilicane (VTMO), and the resulting silylated cellulose sponge (SCS) can be subsequently functionalized with various thiol-containing compounds such as 3-mercaptopropionic acid, via temperature induced thiol–ene reactions. The hydrophilic cellulose sponge thus prepared displayed an excellent mechanical strength of 70 KPa at 80% compression strain. The prepared sponge features hydrophilic and underwater oleophobic properties and was used in gravity-driven removal of oil from oil-in-water emulsions and oil/water mixtures with a high separation efficiency. The separation efficiency remained 100% after 10 cycles for an oil/water mixture and 95% after 6 cycles for an oil-in-water emulsion.

The organosilicon functionalized cyclotriphosphazene (N3P3[NH(CH2)3Si(OC2H5)3]6) was synthesized and characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectra (FTIR), then it was applied to cotton fabrics through a convenient pad-dry-cure process to fabricate flame retardant coating with different add-on values. The coating on cotton fabrics was confirmed by the scanning electron microscopy (SEM). Excellent flame retardancy was found from limited oxygen index (LOI) and vertical burning test. The coating induced an earlier decomposition of cellulose, enhanced the formation of the stable char and significantly reduced the heat release rate. Moreover, flame retardancy of the coated fabrics did not change significantly after 30 soaping cycles.