A new technique for generating regularly spaced crazes to facilitate piece dyeing of polypropylene filaments

The aim of this study was to investigate crazing that generates regular crazes in polymeric fibers. For carrying out this study, we designed and fabricated an experimental apparatus for generating crazes on polypropylene (PP) filaments. By an optical micrograph and a laser scanning micrograph of the surface and cross‐section of the filaments, it was confirmed that the crazes were generated on the surface of the filaments. Optical microscopes and measurements of the craze morphology on the filaments showed that approximately 30–50% of the contact area was crazed. As the crazing tension increased, the interval between the crazes increased, but the width of the crazes did not change significantly. Moreover, it was confirmed that the filaments had a homogenous crazed structure and pores were formed in their structure. The crazing process did not affect the strength of the crazed filaments significantly; the crazing process decreased the light transmittance of the filaments. The acid dyeing was adsorbed onto crazed region of PP filaments. These crazes in the filaments have the potential to lead to new methods for dyeing PP fibers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013