Strong stretching bond force constants and Young's moduli in boron nitride nanotubes

High values of stretching bond force constants (k_r) and Young's moduli ($Y$) for boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs) were determined and compared using density functional theory, focusing on armchair chirality (n,n) within a diameter range of 4.4–13.9 Å. The influence of structural configuration on k_r and $Y$ calculations is discussed, implementing the generalized gradient approximation to clarify the effects and differences in chemical bonding and structural rigidity within BNNTs of different diameters. The results show an increasing trend in the k_r and $Y$ values as the BNNT diameter increases, with k_r magnitudes resembling those reported for CNTs. The theoretical calculations suggest that BNNTs could be an excellent alternative for a broad spectrum of CNT applications, particularly in fields such as energy, electronics, medicine, environmental science, and composite materials, where mechanical properties are crucial.