| Polyamide6(usually known as nylon6, PA-6) fiber is one of the main varieties of synthetic fibers. Numbers of hydrogen bonds are formed due to the regular arrangement of the nylon in the molecular structure so that it has a high degree of crystallinity. PA-6has great advantages of chemical stability and excellent mechanical properties and thermal stability. Nylon6has the largest yield among the nylon products. There is broad market and applications for the preparation of far infrared nylon fiber from nylon6resins. Layered double hydroxides (LDHs) are one type of layered anionic clay, which consisting of layered structures and special physical and chemical properties. Mixed metal oxides (MMO) are prepared by the calcinations of LDHs which have the high specific surface area and strong absorption capability. Especially, there is a large range of choice at divalent or trivalent metal ions in LDHs, the far infarred ceramic powders with excellent infrared emission capacity and wide infrared emission waveband are achieved by controlling the composition of LDHs or MMO.(Zn, Al),(Zn, Mg, Al) and (Mg, Al) layered double hydroxides (LDHs) were prepared by a co-precipitation process, and these bi-or tri-metal oxides were obtained by the calcination of LDHs at500℃. The structure and property of LDHs and MMO wrer characterized by the X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and N2adsorption-desorption isotherm. Then, the high dispersibility far infrared ceramic powders were prepared by organic modification and mixture of different components of MMO mixed with zinc oxide, zirconium oxide and silicon oxide, etc. Infrared radiation properties of the far-infrared nanopowders were characterized by IR-2infrared emissivity measurement instrument and infrared imaging system. The results showed that nanocrystalline MMO particle diameter is between200～500nm with a high specific surface area, the percentage of the coating of coupling agent is about5wt%to10wt%. Measured by infrared thermography method, the surface temperature of composite powders of Mg-Al MMO, SiO2, ZrO2, and ZnO are higher than bare Zn-Al MMO and Zn-Mg-Al MMO powders about2.0to3.0℃, which demonstrated that the former is superior to the latter.Infrared radiation PA-6resins were prepared by the addition of infrared radiation powders (masterbatch method and granulation method) and then melt-extruded. Far infrared PA-6fibers were prepared by the melt spp inning in a composite spinning machine. The results showed that far infrared nanopowders were uniformly dispersed in the PA-6matrix, the average particle diameter of≤500nm, far-infrared radiation PA-6fibers had a good spinnability. However, far infrared radiation nanopowders which were unmodified had a relatively poor dispersion and significant agglomeration in the resins. With the addition of far infrared radiation nanopowders, the strength of PA-6fibers declined from about10%to20%. DSC showed that far infrared radiation nanopowders play the role of "nucleating agent", resulting in crystallization temperature Tc of far-infrared PA-6resins rise, but no effect on the melting temperature of PA-6fibers. Far infrared radiation nanopowders significantly improved the performance of infrared radiation PA-6fibers. Measured by infrared thermography method, for heat preservation at60℃by far infrared PA-6resins, and its temperature is higher than the blank PA-6resin about1.0to3.0℃, with excellent far-infrared radiation properties.Finally, far infrared PA-6textiles were woven through the automatic weaving machine. Infrared radiation properties of different kinds of far infrared PA-6textiles were measured. The measurements of the heating and cooling process by infrared thermography method were performed on different polyamide-6textiles. And then, the main factors which influence on the infrared thermography measurements such as layers, density and weave structure were discussed. The results show that the addition of MMO significantly improved the infrared radiation performance of PA-6fibers or textiles. Infrared thermography measurement showed that the temperature of far-infrared PA-6textiles’surface was higher than the blank surface temperature during the cooling process; wherein PA-6textile contain ZrO2/Mg-Al MMO was3.0℃higher than the temperature of bare PA-6textile mean that it has good infrared radiation performance. Meanwhile, infrared radiation properties of the three-layer textile is significantly less than a monolayer or the two layers textile; infrared radiation properties of the far-infrared PA-6fabric is increased with the increase of density of the textiles; the influence of plain weave or twill weave on the far infrared radiation property of PA-6textiles is light. |
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