Characterization and optimization of cerium oxide nanoparticle-doped cellulose acetate films using the Box-Behnken Design

The demand for UV-absorbing materials has increased due to health concerns and the need for improved protective coatings and packaging. This study develops cellulose acetate (CA) films incorporating cerium oxide (CeO2) nanoparticles (NPs), using acetic acid as a solvent and polyethylene glycol (PEG) as a plasticizer, via the casting method. A comprehensive characterization was conducted using SEM, AFM, EDS, XRD, TEM, SAED, EELS, TGA, DSC, UV-Vis spectroscopy, and tensile testing. The Box-Behnken Design (BBD) was applied to optimize the effects of CeO2 concentration, PEG content, and drying temperature on mechanical, thermal, and optical properties. The films exhibited enhanced UV absorption, with CeO2increasing absorbance at 316 nm, while PEG influenced a nonlinear absorption response at 211 nm. XRD, TEM, and SAED confirmed the high crystallinity of CeO2, while EELS revealed Ce3+/Ce4+ oxidation states and oxygen vacancies, contributing to UV absorption. Thermal stability improved with CeO2, with Tg reaching 252.8 degrees C at 5 wt% CeO2 (+23.3%), while PEG reduced Tg (213.1 degrees C) and degradation onset (341.6 degrees C). Optimized films exhibited superior mechanical properties, achieving 45.39 MPa tensile strength, 2.090 GPa modulus, and 24.38% strain at break, surpassing commercial CA materials. SEM, EDS, and AFM confirmed a well-dispersed CeO2 phase, reducing surface roughness from 22.3 nm to 8.4 nm. These findings demonstrate that CeO2-doped CA films offer superior UV protection, mechanical strength, and thermal stability, making them promising for industrial applications. The integration of BBD with advanced nanomaterial characterization provides a data-driven framework for optimizing multifunctional materials.