Study On The Structure And Properties Of Opaque Polyester False-Twist Textured Yarn And Fabric

The sustained rise of global temperature makes lightweight clothing more and more popular with consumers in summer,but excessive lightness will inevitably result in the lack of visual shielding property,so opaque fibers have emerged.At present,the main method of producing opaque fiber is to add micro-nano particles in the fiber to increase the scattering extinction of the fiber.Two methods are adopted primarily to add particles in the opaque fiber : one is chip spinning,the other is masterbatch spinning.Chip spinning is the process of blending a certain amount of inorganic particles with polymer matrix and then spinning the chips containing certain inorganic particles.Masterbatch spinning is performed by first forming a masterbatch containing a high concentration of inorganic particles,and then spinning the masterbatch with a pure polymer chips.Due to the different particle addition methods may affect the particles distribution in fibers,structure and performance of fibers and fabrics,the structure and properties of opaque polyester textured yarns and fabrics containing white and high refractive index TiO₂ particles obtained through masterbatch spinning and chip spinning were studied in details in this paper.The main conclusions are as follows:?1?Through the results of the scanning electron microscopy and nano-CT three-dimensional imaging tests,it can be found that in case of the same weight percentage of TiO₂ particles added,the particle size of TiO₂ distributed in yarns made by chip spinning and masterbatch spinning are below 500 nm and between 200 nm⁶00 nm respectively.The percentage of TiO₂ particles with a diameter below 200 nm in chip spinning is obviously higher than that in masterbatch spinning,while the proportion of TiO₂ particles between 400nm¹000nm in masterbatch spinning is higher than that in chip spinning.At the same time,by comparing the results of semi-dull and full-dull nylon 6 produced by chip spinning,it is clearly to see that although the mass fraction of the added TiO₂ particles is different,there is almost no difference in the distribution of the particles in thetwo fibers which means that masterbatch spinning is more likely to cause agglomeration of inorganic particles than chip spinning.The solution closest to the refractive index of the fiber was measured by UV spectrophotometer,and then the distribution of inorganic particles in the fiber was observed under the microscope by using the characteristic that the fiber becomes transparent in the solution with similar refractive index.The results show that the refractive index of the solution closest to the opaque polyester fiber was 1.568 and the solution closest to both the semi-dull and full-dull polyamide 6 was 1.542.The experimental results confirmed that the method of making fiber transparent is feasible in measuring the particles distribution in fibers.?2?According to the infrared spectrum analysis,there is no obvious difference in the micro-molecular composition between the opaque polyester fibers made by masterbatch spinning and chip spinning and that of the ordinary polyester fiber.The results of XRD shows that the crystallinity and grain size of masterbatch spinning are higher than that of chip spinning,that is mainly because the dispersion of TiO₂ particles in masterbatch spinning is poor and the agglomeration of particles is favorable for heterogeneous nucleation.The results of DSC and TG show that the glass transition temperature and melting temperature of both the masterbatch and the chip spinning opaque polyester fiber are basically the same,while the crystallization temperature and crystallinity of the masterbatch spinning are higher than those of the chip spinning,however the difference in thermal stability between the two opaque fibers is not distinct.For the physical and mechanical properties,the breaking strength and elongation at break of masterbatch spinning are lower than those of chip spinning,while the friction coefficient is higher.At the same time,the crimp shrinkage rate of the false twist textured yarn of the masterbatch spinning is approximately the same as that of the chip spinning,but the crimp modulus and crimp stability are higher than those of the chip spinning.?3?The visual shielding property of the fabric was tested by both subjective method and objective method as by ultraviolet visible spectrophotometer and colorimeter and the same conclusions have been obtained,that is,the visual shielding property of the grey fabric is lower than that of the finished product,and the visual shielding property of the grey fabric spun by the masterbatch is lower than that of the chip spinning,but in terms of the finished product,the visual shielding property of the masterbatch is better than that of the chip spinning.The thermal insulation of the fabrics was tested by a self-made heat insulation device,and the heat insulation property can be obtained as follows: masterbatch spinning product>chip spinning product>masterbatch spinning grey fabric> chip spinning fabric.The surface roughness of the masterbatch spun product is smaller than that of the chip spinning,the slipping degree is better than the chip spinning,and the compressibility is almost the same as that of the slice spinning.