Analyses of micro-structure and mechanical behavior of polyester pre-oriented filament with dark color by adjusting linear density

The number of fiber components of polyester filaments has an important influence on the strength and feel of filaments and textile products. The number of polyester filaments can be adjusted by selecting the number of spinneret holes on the spinneret plate during spinning. Four kinds of polyester pre-oriented filaments (POFs) with different linear density were prepared from different production lines, named as POF1 (144 dtex/36 f), POF2 (185 dtex/48 f), POF3 (145 dtex/72 f), and POF4 (280 dtex/96 f), respectively. By testing and analyzing these filaments, their differences in micro-structure and properties were discussed. The morphology, molecular structure, thermal properties, and mechanical properties of four kinds of polyester POFs were characterized by means of scanning electron microscopy, Fourier infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, filament color, and mechanical properties. By analyzing the difference of four kinds of polyester POF with different linear density in various characteristics, it provides guidance for the industrial production of polyester filament and the improvement of filament level. Experimental results show that they have smooth overall appearance, no major defects, and good spinnability. The degrees of order of the four kinds of polyesters were all lower than 5%. The degrees of orientation of the four kinds of polyesters were all about 80%. In terms of thermal properties, the larger the linear density is, the higher the melting temperature is. For color results, the higher the reflectance value of polyester filaments, the darker the color of polyester filaments. In addition, the breaking elongation and static and dynamic friction properties of POF1, POF2, and POF4 are close and they are all larger than POF3, which may be explained bf the fact that the linear density of polyester POF3 is significantly lower than that of the other three polyester POFs.