Surface Modification Of Titania With Organic Amines And Their Applications In Full Dull PA6 Fiber

Fiber as one of the essential materials in life,from the original natural fiber to the widely used synthetic fiber,has formed a huge market of output value.With the improvement of people’s living standard and consumption quality,the consumers have higher demands on the aesthetic degree of fiber fabrics.Because ordinary fiber produces partial total reflection to incident light,it is difficult to meet the requirements of people because of its dazzling luster.By changing the internal structure of fiber,refractive index and adding dull agent,the fiber with full dull property can be prepared and the reflection phenomenon can be reduced.Among the common extinction fibers,Nylon has almost the best mechanical properties,and it has wear resistance,high fracture strength,good elasticity,which in underwear,coat and other markets is very popular.Due to its large production,low cost and large difference between refractive index and fiber surface,titania has become one of the most commonly used extinction agents.The effect of total extinction can be achieved by adding 1.5~2.0 wt% titania into the fiber.However,titania particles are easy to be agglomerated by van der Waals force and surface action,and are not easily dispersed uniformly in fiber forming polymers,which makes the spinning process not smooth.In this paper,three kinds of polyamines and three coupling agents are used to modify the surface of titania.By studying the graft amount of modified titania,particle size distribution,Zeta potential and settling height in the dispersion,the suitable programme is selected for the next step of polymerization with caprolactam to prepare the full dull resin chips and melt spinning.Finally,the polyamide fiber with total full dull property is obtained.The particle size D50 of titanium white powder is about 300 nm after grinding in nanometer grinding machine for 30 min,which is within 1/2 visible wavelength,and the chip had the requirement of both full dull and spinnability.The absolute values of Zeta potential of titania modified by 1,12-Dodecanediamine and Titanium bis(triethanolamine)diisopropoxide are 38.13 mV and 37.27 mV,respectively.The grafting amount of organic matter is 1.504 wt% and 1.566 wt%,respectively.And the two samples have compact and uniform surface morphology and good dispersion in caprolactam aqueous solution,Therefore,the above two kinds of samples are selected for polymerization.The full dull polyamide chips are made by adding titanium dioxide and caprolactam into polymerization kettle under ring opening polymerization at high temperature and high pressure,and full dull polyamide fibers are prepared by twin-screw extruding mechanism.After adding the modified titania,the crystallinity of the slice decrease to a certain extent.,and the viscosity and the relative molecular weight increase.By observing the surface and cross-section of chips and fibers,it can be found that titania is dispersed on its surface uniformly,and there is no obvious agglomeration.In addition,the breaking strength of the fiber added with titania doesn’t decrease significantly,and the elongation at break increase to 33.14% and 16.38% respectively.Compared with the bright nylon fiber,we can find that the diffuse reflection of the total extinction fiber is obviously improved.