Characterization of structure and properties of dark color polyester FDY with varied linear density

Linear density, as an important index of industrial filament production, has a vital impact on the performance of filament products, but there are few relevant studies. In order to further investigate the effect of the change of linear density on the performance of polyester filament in the process of industrial filament production. By replacing different spinnerets, five kinds of polyester full-stretch filament with different linear densities were prepared and named FDY. By testing and analyzing five kinds of polyester FDY filament, the differences in structure and properties of five kinds of FDY filament are discussed. The morphology, molecular structure, thermal and mechanical properties of five kinds of polyester FDY filaments were characterized by means of scanning electron microscopy, Fourier infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, filament color and mechanical properties. The results show that the molecular structure, crystallinity and orientation of polyester FDY filament are not affected by changing the linear density by changing the spinneret. In terms of heat, the melting point temperature and enthalpy of polyester FDY filament increase as linear density increases. In terms of optics, the lower the linear density of FDY, the lower the reflectivity of FDY. As the wavelength increases, the reflection of FDY decreases first and then increases. The reflectance is minimal when the wavelength is 670 nm. In terms of mechanical properties, the breaking strength and elongation at break of polyester FDY decrease with the decrease of linear density. In this study, it is found that changing the linear density by changing the spinneret has specific effects on the performance of polyester filament in various aspects, which has guiding significance for the analysis of influencing factors on the performance of industrial filament in the process of industrial production.