Fabrication of strong nanocomposite films with renewable forestry waste/montmorillonite/reduction of graphene oxide for fire retardant

Abstract

It is desirable to develop products comprised of biodegradable components from green resources or renewable waste due to a shortage of fossil fuel. Wood auto-hydrolysates (WH) are generated in the hydrothermal treatment of the pulping process, which contains large amounts of hemicelluloses and some lignin. In this work, a green and facile route similar to paper making is proposed to convert WH to value-added nanocomposite films. WH was combined with montmorillonite (MMT) as the basic components together with a small quantity of graphene oxide (GO) to produce a ternary, bioinspired nanocomposite film with high strength and fire resistance properties. GO was initially introduced to fabricate the WH-MMT-GO nanocomposites, the interfacial interaction between WH, MMT, and GO was enhanced by the synergistic effect of hydrogen and covalent bonds. The nanocomposite film WH-MMT-rGO (F0.8%rGO) with only 0.8 wt% rGO exhibited promising features, such as a good thermal stability, and a high strength of 124 MPa, which was better than other hemicellulose-based films or wood auto-hydrolysate based films. The combustion behavior of WH-MMT-GO films was determined by microscale combustion calorimeter (MCC), and the results suggested the films had excellent fire resistance, where the peak heat release rate (PHRR) of the films was reduced by more than 90% compared to the neat WH. Furthermore, the hemicellulose-based films are reported to be hydrophilic, while the WH-MMT-rGO films proved to be hydrophobic due to the introducing of rGO. The proposed synthetic strategy could make the wood auto-hydrolysate useful for fabrication of fire-protective films, coatings, packaging, etc.