Characterization and optimization of cerium oxide nanoparticle-doped cellulose acetate films using the Box-Behnken Design
Lívia Viana Aguiar de Oliveira, Noemi Raquel Checca Huaman, Sérgio Neves Monteiro, Ulisses Oliveira Costa, Letícia Vitorazi
Abstract
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 CeO₂ increasing 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 °C at 5 wt% CeO₂ (+23.3%), while PEG reduced Tg (213.1 °C) and degradation onset (341.6 °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.