| The melt spinning of PP and PS with some functional component, not only can significantly improve the dye ability of PP fibers, but also give it certain functionality, such as anti-bacterial anti-static, anti-UV, anti-permeability and so on. The performance of blend fibers mainly depends on the morphology of dispersed phase, so many researchers concentrated on the factors of morphology of dispersed phase in blend fibers, but the morphology evolution of dispersed phase in spinning line had less concerns. A further study on the morphology evolution can enrich and develop the evolution mechanism of dispersed phase in extension field, and guide the material processing. Our research group has studied the morphology of dispersed phase in the extruded fibers and take-up fibers. Based on these, this work focuses on the morphology evolution by means of on-line sampling, at the same time, the influence of content of dispersed phase and draw ratio on the morphology evolution was discussed. The main research contents and conclusions are summarized as below:(1) The preparation of PP/PS blend fibers and the establishment of sampling methods on spinning line. PP/PS blend fibers were prepared by melt spinning with draw ratio from11.78to94.25and the contents of PS from4.0%to8.0%. The fibers were collected within70cm from spinnerets by the fibers sampler which is designed by us. An appropriate on-line sampling method was established.(2) The evolution of morphology of dispersed phase. After resin embedding, frozen ultrathin slicing, and etching, the morphology of dispersed phase was observed by SEM. In the extruded fibers, the dispersed phase distributes in PP matrix phase as sphere with the typical "sea-island" structure, the histogram of droplets diameter distribution is in fine with log-normal distribution. With the increasing of PS content from4.0%to8.0%, the number of droplets increased from347to436, the diameter of droplets increased from2.43μm to2.90μm, and the diameter distribution broadened. In the fibers on the spinning line, the dispersed phase distributed in PP matrix phase as ellipsoid. Along the spinning line, the number per unit area and the diameter of droplets decreased, the aspect ratio increased. Within10cm from spinnerets, the morphology varies fastest, the variation slow down within10cm to50cm and remains stable after50cm.(3) The effects of content of dispersed phase and draw ratio on the morphology evolution. At the same position in the spinning line, along with the increase of content of dispersed phase, the number of per unit area and diameter of droplets increase. With the increase of aspect ratio, the number of per unit area and diameter of droplets decrease. With the increase of the content of dispersed phase and the draw ratio, the last aspect ratio increasing from2.06and1.79to2.32and2.62respectively, at the same time, the morphology variation degree increased. |
