Wet spinning of aliphatic and aromatic polyamides



Bench-scale equipment for wet spinning was designed and built. An experimental study of the wet spinning of several polyamides has been carried out. The polymers studied include nylon 6, nylon 66, redissolved Nomex, and redissolved Kevlar. The superstructure of the wet-spun fibers were studied by optical and scanning electron microscopy as well as small- and wide-angle x-ray diffraction. Mechanical properties were measured and related to the spinning variables. For nylon 6 and nylon 66, the coagulation bath composition was found to be of major importance in determining fiber superstructure. For the case of the redissolved Kevlar, anisotropic spinning dopes were obtained from redissolved fiber, and the wet-spun filaments produced from such solutions were investigated. These fibers proved to have relatively high modulus and strength as spun. They had even greater strengths after hot drawing.