Synthesis and characterization of magnetic nanoparticles/dialdehyde cellulose composite as a flame retardant

The objective of this study was to prepare innovative benign magnetic nanoparticle (MNPs, Fe₃O₄)/dialdehyde cellulose (DAC) composite to enhance flame retardancy. The (Fe³⁺/Fe²⁺) coprecipitation was used to prepare the composite MNPs/DAC. The FT-IR, Raman spectroscopy, x-ray diffraction (XRD), SEM, TGA, and DTA were used to confirm and characterize the prepared composite. Remarkably, the DAC was applied in an intramolecular Cannizzaro reaction during in situ generation of MNPs in the presence of concentrated sodium hydroxide solution to generate hydroxy acid. However, the computational study preferred the generation of a carboxylic group at C3 rather than C2 in the disproportionation reaction. The XRD analysis of MNPs/DAC indicated the significant modification results in the DAC phase. Furthermore, DSC and TGA clarified that the heat of combustion for the DAC was clearly higher than that of the MNPs/DAC composite. Moreover, the presence of MNPs in the composite effectively increased the char yield from 8% in the DAC to 25% in the composite in a temperature range of 600 °C–800 °C and decreased the gas-phase products. Furthermore, the SEM microscopic images confirmed the homogenous distribution of MNPs onto hydroxy acid, which revealed the crucial role that MNPs played in increasing the flame retardancy of the composite. (paper)