Regarding the change of crystallinity and average crystallite size occurring at polycaprolactam filaments by the cold drawing process

Abstract Changes of crystallinity and average crystallite size which occur in polycaprolactam filaments during the cold drawing process are analyzed. The estimation of fiber crystallinity was carried out by use of the differential‐filtration x‐ray method. The crystallite size was evaluated on the basis of the broadening effect of Debye lines from x‐ray powder‐method diagrams and from the large identity period interferences obtained by small‐angle scattering patterns. The results obtained show that with the change of draw ratio the crystallinity and the average crystallite size also change. The highest values of crystallinity and average crystallite size were found at 375% nominal draw (315% real elongation). The total increase in crystallinity in comparison with the undrawn state of a filament is approximately 27%.