Synthesis and Characterization of Cellulose Microcrystals–Chromium Oxide Nanocomposites: Enhancing Surface, Thermal, and Optical Properties

This study developed a novel nanocomposite with expected potentially broad applications in different fields by synthesizing biopolymers cellulose microcrystal@chromium oxide (CMC@Cr2O3) and activated cellulose microcrystal@chromium oxide (ACMC@Cr2O3) nanocomposites using an environmentally friendly facile sonication method. The effects of activation of CMC on the characteristics of synthesized Cr2O3 nanocomposite were also examined in the study. The creation of CMC@Cr2O3, and ACMC@Cr2O3 were investigated employing FTIR, DRS-UV-Vis, SEM, EDX, mapping, XRD, VSM, and TGA techniques. These studies illuminated the optical properties, particle size distribution, crystallinity, and thermal stability and the results demonstrated higher thermal stability, paramagnetic properties, and semiconductor nature properties. Also, surface enhancing was observed upon monitoring some structural parameters extracted from powder x ray diffraction study. The magnetic hysteresis analysis revealed paramagnetic behavior in CMC@Cr2O3 and ACMC@Cr2O3, as neither exhibited magnetic saturation at the maximum field. Further examination indicated that the activation process significantly influenced the magnetic properties, with ACMC@Cr2O3 displaying lower saturation magnetization (Ms), reduced remanent magnetization (Mr), and lower coercivity (Hci) compared to the non-activated CMC@Cr2O3 sample. These variations are attributed to the activation process altering the ionic environment, chain conformation, and structural network of the polymer matrix, resulting in diminished magnetic responses. Moreover, changes in nucleation and growth processes of Cr2O3, as evidenced by SEM and mapping analyses, alongside the activation-induced modifications in the polymer matrix, appeared to hinder the formation of larger or more optimally aligned magnetic domains. Structural enhancements, as inferred from powder X-ray diffraction data, were also observed, supporting these findings.