Study On The Morphology Of PP/PS Blend Fibers In Different Out-fields Processing

Polypropylene (PP) fibers have had significant success in the technical textiles sector with wider and wider application. Many studies were focused on modification of PP fiber to overcome its poor properties. Among the numerous modified methods, preparation of PP blend fibers was the most efficient and convenient one. For the blends morphology had strong relationship between polymer formation and final properties, otherwise the majority of PP blends were uncompatibility, so morphology became hot-point for the research of PP blend fibers especially for modification PP fibers.In this paper, based on the study of interfacial characteristic, viscosity and crystallization, the investigation of the surface and inner morphology for pure polypropylene(PP), polypropylene/polystyrene (PP/PS), polypropylene/hybrid polystyrene ( PP/Hy-PS) blend fibers were carried out, which was effected by different processing out-fields such as take-up velocity and surrounding temperature. The morphology behavior and distribution of dispersed phase in PP/PS blend fibers were characterized using the scanning electron microscopy (SEM), polarized optical microscopy(PLM), atomic force microscopy(AFM), Wide-angleX-ray scattering (WAXS) and differential scanning calorimetry (DSC).In the research of interfacial characteristic, the interface tension of PP/PS was estimated using Guggenheim and MacLeod equation and validated by Cohen-Carrier model. For the existence of nano particles, the interface tension of PP/Hy-PS was much lower than that of PP/PS. The rheological properties of PP/PS and PP/Hy-PS were studied using rheometer to confirm the temperature at which the viscosity ratio of PP/PS was equal and the processing temperature. The study of blends crystallization kinetics showed that the crystallization rate decreased with the increase of temperature and PS content. Furthermore there were minimums of crystallization rate constant and crystallinity.Under the processing out-field effects, the spherulitic structure changed to shish-kebab structure accompanying while the crystal transiting from a to paracrystalline which include the a and 13 crystal, then the paracrystalline changed to a crystal with take-up velocity increased continuously. These were observed in both PP fibers and PP/PS blend fiber and the presence of PS in blend fibers accelerated such transformation. With the variation of take-up velocity and PS content, the dispersed phase appeared fibrillar structure which was obvious gradient structure along radial direction in fiber crocess section, such as in the blends fiber(92/8) the gradient phase distribution of PS was observed from the 40nm(center) to above l00nm(surface). The higher temperaturecould accelerate the paracrystalline formation and morphology transition, nevertheless the effect of blowy temperature was more conspicuous than processing temperature.In the study of PP/Hy-PS blend fibers, the morphology and structure variety tendency of that were similar with PP/PS blend fibers, and the nano cerium dioxide was observed in the surface and matrix of blend fibers.