Reduced graphene oxide/cellulose microfiber hybrid from the Vietnamese Nipa palm tree: Synthesis, properties, and applications for preparation of poly(methyl methacrylate) composite

Abstract

Cellulose microfibers were successfully fabricated from Vietnamese Nipa palm by mechanical and chemical treatments. The Nipa palm petioles were simply rolled, pressed, and separated. They were then pretreated with an alkaline solution and submitted to acid hydrolysis to remove the impurities (tCell). The microfibers were reinforced with reduced graphene oxide to form a hybrid that was reduced with hydrazine hydrate in the last stage (tCell-rGO). The structure and properties of tCell and tCell-rGO were evaluated by FTIR, XRD, DSC, TGA, SEM, BET, and the sheet resistance. It was observed that the treated cellulose microfibers exhibited a diameter of 10–20 μm and had good crystallinity in the structure. Both tCell and tCell-rGO exhibited low-density values of 1.52 kg/m3 and 0.58 kg/m3, respectively, and had good specific surface area values of 11.2 m2/g and 13.0 m2/g, respectively. These results supported the decrease in the density and the increase in the specific surface area of the tCell-rGO samples in comparison with the tCell. The existence of rGO sheets in the cellulose microfiber matrix resulted in changes in the structure, arrangement, and crystallization of pristine microfibers. The thermal property and electrical conductivity of the reinforced GO cellulose microfibers were significantly improved. rGO not only showed its role as a surface modification agent that helps the cellulose microfibers disperse better in the non-polar substrate, but also contributed to the increase of the heat-stable and mechanical properties of polymer. The thermal stability of tCell-rGO/PMMA composite was notably improved more than 40°C in maximum decomposition temperature by an emulsion polymerization technique. The material based on cellulose microfibers from the Vietnamese Nipa palm tree and reduced graphene oxide overcame some disadvantages such as the poor heat resistance, poor dispersion of the original fibers in the non-polar polymer and displayed great potential for environmentally friendly future applications.