While poly-L-lactic acid (PLLA) is being developed for use in various medical devices, there is still an urgent need to elucidate the correlation between molecular chain deformation behavior and mechanical properties such as stress. In addition, there have been few published studies where molecular dynamics simulations were used to compare the molecular chain deformation behavior, which is difficult to evaluate in the micro region, and the potential energy and evaluate mechanical properties like stress. Therefore, in this study, in order to study the molecular chain deformation behavior of PLLA using molecular dynamics methods, analysis models of initial orientation 0º, 45º, 90º and four randomly oriented models were prepared. In addition, tensile simulations were carried out using affine deformation, and the influence exerted by molecular chain deformation behavior on the mechanical properties was evaluated. Molecular chain deformation behavior, molecular chain length, molecular chain angle, and the distance between centers of gravity of different molecular chains were determined and compared with the potential energy and stress generated in tensile simulations to evaluate the mechanical behavior. As a result, it was found that the model showing curing behavior exhibited increased stress after reaching the lower yield point, while the model not showing curing behavior exhibited a remarkable increase after the stress reached the lower yield point. In addition, it was suggested that the elongation and angle change of the molecular chain had a large influence on the stress, and that among these factors, the angle change exerted the largest influence on the stress.
