The nascent structures of poly(epsilon-caprolactam) (N6), obtained during anionic polymerization in bulk in the presence of different additives, were investigated. The experimental data show that both the type and the quantity of activator influence significantly the process of polymerization as well as the chemical and the physical structures of N6. By means of WAXD, DSC, IR, light and transmission microscopy (TEM), and electron microdiffraction (ED) the changes in the morphological and the crystal structure were followed. The observed alterations in the physical structures of N6 samples are explained on the base of changes in the chemical structure and mobility of the polymer chains.