Thermal Stability and Mechanical Properties of Poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) Modified by Fe2O3 Nanoparticles

In this study, molecular dynamics (MD) simulation is used to investigate the effect of Fe2O3 nanoparticles (NPs) on the structural and thermomechanical properties of poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) nanocomposites. Five molecular models of pure PHPMA and PHPMA/Fe2O3 nanocomposites with different NP sizes and concentrations were constructed and analyzed. The dynamics of the various models were investigated using mean square displacement (MSD), and their glass transition temperature (T-g) was estimated using both density-temperature and MSD evaluation methods. The results reveal that the presence of Fe2O3 NPs enhances the molecular mobility and flexibility of polymer chains within the PHPMA matrix and decreases their T-g. Additionally, the introduction of Fe2O3 NPs significantly reduces the mechanical properties, such as Young's and bulk modulus, of the PHPMA polymer. Furthermore, the study demonstrates that the impact of NPs on polymer properties is strongly influenced by NP features; an increase in NP size and concentration correlates with enhanced molecular mobility and flexibility, while T-g and mechanical properties exhibit a negative correlation with these parameters. These findings offer valuable insights into the influence of Fe2O3 nanoparticles on the structural and thermomechanical properties of PHPMA nanocomposites, providing a foundation for optimizing their design and applications across various fields.