Effect of coagulation conditions on properties of poly(acrylonitrile-carboxylic acid) fibers

Acrylic fibers are among the most useful synthetic fibers ford textile applications, and special acrylic fiber (SAF) has industrial applications. The physical and mechanical properties of fiber are affected by several parameters; one such parameter is coagulation conditions: bath temperature, bath composition, and drawing. Acrylonitrile-carboxylic acid copolymers, that is, acrylic methacrylic and itaconic acid, were converted into fibers using the dry-jet wet spinning technique. The coagulation bath temperature vas varied from 5degreesC to 35degreesC, and the properties of the fibers so obtained were investigated. The effect of the final drawing ratios (6.5 and 8.5) on such physical and mechanical properties as tenacity, sonic modulus, initial modulus, density, crystallinity index, and X-ray orientation were also investigated. In addition, thermogravimetric analysis and scanning electron microscopy were used to determine the thermomechanical properties and fracture morphology of the fibers. (C) 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1825-1837, 2003.