Fully bio-based chitosan/sodium alginate coating for flame retardant Xuan paper

Abstract

The development of bio-based flame retardants has received increasing attention. In this study, fully bio-based chitosan/sodium alginate (CS/SA) coating was applied by layer-by-layer (LbL) assembly on Xuan paper to improve its flame retardancy. The LOI value of Xuan paper reached 33.3% after 20 BLs CS/SA coating. Its char length was reduced to 8.8 cm with no after-flame and after-glow. These results showed that the flame retardancy of Xuan paper was greatly improved by LbL assembly CS/SA coating. Thermogravimetry results revealed that CS/SA coating on Xuan paper slowed down the thermal degradation process and promoted the char formation both under nitrogen and air atmosphere. The stable char layer formation by CS/SA coating covered on the Xuan paper inhibited the heat transfer and diffusion of combustible gases, showing obvious condensed phase flame retardant action. Scanning electron microscopy confirmed that CS/SA coating on paper fiber promoted the char formation to form the stable covering layer. Furthermore, the CS/SA coating formed non-flammable gases to enhance the flame retardancy of Xuan paper, showing a certain gas phase flame retardant action. This research provides a new approach for fire-resistant Xuan paper by using fully bio-based compounds.

Mechanical and barrier properties of chitosan-based composite film as food packaging: A review

“…With excellent filmforming characteristics along with selectivity and permeability towards CO2 and O2 gases, coupled with remarkable antibacterial properties, chitosan can be directly applied for packaging purposes, thereby enhancing both food safety and shelf life (Aguirre-Loredo et al 2016;Fauzi et al 2019;Vijayakumar et al 2022). Several strategies have been proposed to enhance the functional properties of chitosan films and broaden their potential applications, such as modifying the degree of deacetylation, pH, solvent selection, and incorporating plasticizers or other components such as proteins or polysaccharides (Pelissari et al 2009;Wang et al 2015;Lopez-Mata et al 2018;Liu et al 2022). The aim of this work was to review the literature on mechanical and barrier properties of chitosanbased composite films.…”