Study of the structure development during the melt spinning of nylon 6 fiber by on-line wide-angle synchrotron x-ray scattering techniques

The melt spinning of nylon 6 has been studied with on-line wide-angle synch rotron X-ray scattering techniques. The apparatus consisted of a single scr ew extruder and a metering pump mounted on a horizontal platform that could be translated in the vertical direction allowing a range of distances to b e sampled with the X-ray beam. The structure development, equatorial crysta llinity index, and crystalline orientation were studied as a function of ta ke-up speed and position along the spinline. For low-speed (50 mpm) situati ons, the nylon chains crystallize into independent hydrogen bonded sheets t hat start to interact with each other as their concentration starts to incr ease. For higher speed situations, the nylon chains crystallize directly in to the interacting hydrogen-bonded sheet structure. Upon conditioning at ro om temperature for 24 h, this interacting hydrogen-bonded sheet structure t ransforms into the well-known three-dimensional alpha and gamma phases of n ylon 6, probably existing in a shish-kabob structure. The equatorial crysta llinity index increases as distance from the spinneret increases and as tak e-up speed decreases. The crystalline orientation function is constant alon g the spinline for a constant take-up speed, and increases as take-up speed is increased. Conditioning further increases both the crystallinity and cr ystalline orientation of the fibers. (C) 1999 John Wiley & Sons, Inc.