Effect Of Surface Modification Of Titania On The Properties Of Full Dull Pa6Fibers

Polyamide6fiber, usually known as nylon6or PA6, is one of the main varieties of synthetic fibers. Due to PA6has great advantages in chemical stability, mechanical properties and thermal stability, product made of nylon fiber has good elasticity, high strength, wear resistant, durable and small specific density etc., which made them popular among lots of consumers. But there is a common problem about the fiber as it often shows intense colour and lack of overhanging sense. Therefore, nylon fiber product sometimes cannot meet our sensory requirements on clothing. To solve the above mentioned problem, we try to do some modification for composition and structure of the fibers. With the development of nanocomposite material, both semi-dull and dull fiber products by adding certain inorganic materials to the fiber are available. At present, the most commonly used additives is anatase titanium dioxide (in particle size of200-500nm) as it has many strengths such as high refractive index, insolubility, chemical inertness and nontoxicity. In recent years, polyamide products are also widely used in the high-grade textile industry, contributing to the development of the full dull polyamide products.However, inorganic nanoscale powder always tends to agglomerate due to their small particle size and huge specific surface area. Meanwhile, the surface groups of inorganic powder are different from the caprolactam, so the dispersion and interface compatibility of the particle will influence the properties of the semi-dull and full dull fiber. Through inorganic coating and organic modification of titanium dioxide respectively, we can improve powder reunion by using organic functional groups steric of titanium dioxide surface. At the same time, the coating of titania with organic functional groups improves the compatibility between the particles and nylon matrix. It has great value for enterprises to develop polyamide fiber with good mechanical properties, high dyeing rate and high color fastness.In this paper, our works concluded the refining treatment of TiO2, amorphous coating, binary coupling agent surface modification, as well as the situ polymerization for the full dull PA6resin, and the melt spinning for the full dull PA6fiber. Finally, the effect of surface modification of titania on the mechanical properties and dyeing of the full dull polyamide fabric was investigated.First, the coating of amorphous TiO2and organic modification with different complex formulations coupling over titania were carried out. Then we can get corresponding matting agent. The structure and property of modified TiO2were characterized by Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TG), dynamic light scattering, UV-vis absorption spectrum and sedimentation experiment. The results showed that the size distribution of TiO2particle modified with the binary coupling agent become narrow, and shifted to a finer particle size ranging from300nm to500nm. the coating percentage of coupling agent was about4wt%measured by TG. According to photocatalytic performance, it shows that catalytic activity of titanium dioxide is significantly reduced after organic coating and the modified titanium dioxide was well dispersed in caprolactam-water solution.After in-situ polymerization of caprolactam in the presence of the modified titanium dioxide, we can obtain the full dull PA6resin chips, then we melt spinning on composite spinning machine and produce full dull PA6fiber. By adding titanium dioxide, the relative viscosity and the number average molecular weight for PA6resin is largely enhanced. Through DSC curve, it shows that it has no much influence on Tm of PA6fiber after adding titanium dioxide, but it will increase Tc and Xc. Modified powder is evenly distributed in the fiber cross-section without any shedding, so the spinning ability of dull PA6fiber is good. However, unmodified nano-powder dispersion is relatively poor with a clear reunion. After adding modified titanium dioxide, the mechanical strength and elongation of PA6fiber is increased. The mechanical strength can reach4.1cN/dtex and the broken elongation can reach28.1%.Finally, thorough full dull PA6textiles made by auto weaving machine, we study the dyeing performance and color fastness before and after modification. The crystal phase of full dull PA6fabric have changed and the a crystal increased after heat setting, but the total crystallinity basically remain unchanged. From dyeing properties, we concluded that the dyeing effect for both light and dark color is the best while dyeing with acid blue. Because the percent of dyeing is high, the dyeing rate is quick, and just need a short time to reach dyeing equilibrium. Furthermore, the exhaustion and dyeing rate of modified titania PA6fibers were higher than unmodified PA6fibers. PA6fabric has better friction resistance before and after modification and it can reach level5. However PA6fabric after modification and dyed from medium and dark dye ware has better color fastness to light and it can reach level4to5.