Thermal stability modeling of high molecular weight polymethylmethacrylate TiO ₂ nanocrystals nanocomposites: Effect of loading and morphology

Abstract In this work, we investigated the thermal degradation of high molecular weight polymethylmethacrylate (HMW‐PMMA) nanocomposites reinforced with titanium dioxide (TiO ₂ ) nanoparticles (NPs) in two morphologies, namely nanodots (NDs) and nanorods (NRs). Thermogravimetric (TG) measurements were studied by using a weight loss kinetic model based on the isothermal Lyon approximation. The combination of experimental data and theorical calculations allows for the evaluation of significant thermodynamic parameters, including entropy, activation energy, Gibbs free energy, and enthalpy. The obtained results show that the thermal stability of the HMW‐PMMA improves by adding increasing TiO ₂ NP loading amounts into the polymeric nanocomposites. Interestingly, the thermal stability is also affected by the specific nanoparticle morphology, as adding spherical shaped TiO ₂ NDs leads to a superior resistance to thermal degradation than elongated TiO ₂ NRs, due to the larger surface area of TiO ₂ NDs and their reduced tendency to aggregate within the polymeric host. Finally, our findings demonstrate the relevance of the systematic study and careful selection of nanofiller morphology and concentration in optimizing the thermal properties of PMMA‐based nanocomposites. Highlights Solid state nanocomposite films of PMMA and colloidal TiO ₂ NPs were fabricated Thermal degradation was studied by TGA measurements and theoretical simulations Thermodynamic parameters were evaluated by experimental data and simulations Increasing NP loading in PMMA enhanced the thermal stability of nanocomposites Specific morphology of TiO ₂ NPs affects thermal stability of nanocomposites