Beyond conventional models: Innovative analysis of tensile strength for polymer hydroxyapatite nanocomposites

Limited models exist for specifying the mechanical properties of hydroxyapatite (HA)-filled nanocomposites. However, previous articles have not suggested a simple, accurate and reasonable model for the tensile strength of HA-reinforced samples. Also, the impacts of HA size and interphase properties (thickness and strength) on the strength of these nanocomposites were ignored in the earlier articles. The present article advances a model for the tensile strength of HA polymer nanocomposites, taking into account the interphase area. The proposed model is defined by HA concentration, HA radius, and interphase properties, including thickness and strength. In fact, the proposed model considers the reinforcing efficacies of both HA and interphase. The developed model is validated through empirical results for actual samples and parametric studies. The strength of nanocomposites is directly influenced by the interphase thickness (t), interphase strength (σ_i), and HA concentration, regardless of HA radius (R). The greatest strength improvement (200 %) occurs with the smallest HA radius and thickest interphase (R = 6 nm and t = 10 nm), as well as R = 6 nm with the strongest interphase (σ_i = 30 MPa). Moreover, the thickest interphase and the highest HA concentration (t = 10 nm and ϕ_f = 0.02) double the strength of the system. All parameters reasonably affect the sample strength, confirming the validity of the developed model.