Influence of processing on structure of β-nucleated poly(propylene) fibers

Fibers colored with quinacridone pigment spun at low take-up velocities were obtained. The spun fibers, with a very high β-form content, were drawn at room temperature and at a temperature of 120°C at different draw ratios. They were then heat stabilized at different temperatures, ranging from 140 to 150°C for different time intervals. As a result of drawing, the transition from β to mesophase, as well as that from β to α, was observed. The β to mesophase transition results from cold drawing at room temperature, while the β to α transition results from drawing at 120°C. In both cases, the significant decrease of β-form content occurs at the low draw ratio of 2. At higher draw ratios, the β-form content gradually decreases, and at a draw ratio of 7 the β-form disappears altogether. As a result of heat stabilization, the β to α transformation was observed. The first change of the β-form content was noticed at 140°C. For fibers stabilized at temperatures above 140°C, the decrease of the β-form content is more significant and increases with the increase of the stabilization temperature. At 150°C, a rapid drop of the β-form content occurs after only 3 min, and after a few more minutes the β-form disappears. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1413–1418, 2004