Polyurethane – antimony tin oxide composite material to help you hide stature
With the development of science and technology, national military strength. Now, remote BVR combat has become the mainstream. Long-range reconnaissance measurement technology and a variety of stealth technology is increasingly important, and infrared stealth technology is an infrared radiation emitted by objects as similar as possible with the surrounding background radiation technology, so that the infrared detection sensors can not distinguish between the target object. Material 
comprises an infrared shielding coating a metal powder, a conductive polymer, an organic / inorganic composite material and a semiconductor. Considering the weight of the material aspect, the infrared shielding capability and mechanical properties, antimony tin oxide synthesized by various techniques (ATO) nanoparticles are widely used in infrared and thermal radiation shield coating. Currently unresolved problem is that when mixing the nano ATO particles with the polymer matrix, the mechanical properties of the fibers may be degraded. Therefore, it is necessary to develop a wearable infrared (IR) radiation shielding material for heat and which can be increased without significant fiber weight, while maintaining the mechanical strength of the fibers, effectively improving shielding efficiency.
Highlights
Gyeonggi University Korea Sang-Mi Jeong and other researchers succeed synthesis of polyurethane – antimony tin oxide (PU-ATO) composite fibers , as compared with conventional polyester fabric or PU, the research and development of PU-ATO composite textile fibers having and excellent heat radiation shielding properties IR [123 ], even when is exposed to -20 ° C and + repeating temperature to 80 ° C for 30 days and the long-term temperature changes ten cycles, PU-ATO composite fibers still having a heat stable and IR radiation shielding performance. PU-ATO composite fiber surface is made hydrophobic, in order to prevent the PU-ATO composite fibers absorbed water wetting and cause thermal IR radiation modification. 
Preparation procedure PU-ATO composite fibers As shown, by controlling the concentration of the precursor and the ATO sol 1– sol-gel method of the aging time, get the best ATO sol. The PU mixed with a predetermined amount of the sol solution obtained composite PU-ATO suspension having a different composition. Wet spinning technique, four different ATO concentratedOf (0.5,1.5,3.0 and 4.0 mmol) of the compound as starting material a suspension, a PU-ATO (1-4) Preparation of composite fiber.
Preparation of
FIG. 1 ATO sol and PU-ATO composite suspensionIR PU-ATO composite fiber and the heat radiation shielding characteristics [ 123] as shown in FIG 2, when used in the visible and infrared camera to observe people, when covered with a conventional polyurethane or polyester fabric, infrared and thermal radiation emitted by the human body will become visible through the fabric. Conversely, when part of the body covered by clothing PU-ATO composite fiber, infrared and thermal radiation emitted by the human body is shielded, not recognize human IR profile.
Hydrophobic PU-ATO composite fiber [123 ]
IR image deformation, hydrophobic fibers and is essential for the infrared heat radiation shielding capability since the fibers maintain a certain level of water absorption will result. Using a contact angle analyzer evaluate wettability of the composite fiber. 4, different concentrations (0.5,1.5,3.0 and 4.0 mmol) of PU-ATO (1-4) water contact angle of the composite fibers are ≥130 °, exhibits hydrophobicity, and therefore, water droplets on the surface of the fabric not absorbed, butEasy to tumble.
Water 4 PU-ATO composite fiber of FIG contact angle schematic
for use as a practical wearable textiles, textile products and must maintain its infrared heat radiation shielding performance in different environments. 5A, after repeated exposure to high (+ 80 ° C) and low (-20 ° C) temperature, the surface temperature of the PU-ATO (3) of textile composite remains stable. These results confirm that, even after repeated exposure to high temperatures and low temperatures, and infrared heat radiation shielding properties of the composite textile still maintain. 5B shows a continuous infrared heat radiation shielding performance and PU-ATO (3) of the textile composite. At a temperature of 40 ° C for 8 hours a day, for 30 days, the surface temperature of the fabric is measured. The results showed that even for a long period of time, the surface temperature of the fabric is maintained at about 25 ° C.
FIG 5 according to changes in temperature and time, and repeated assessments of infrared heat radiation shielding performance PU-ATO (3) of the textile composite. A, after repeated heating (+ 80 ° C) and cooled (-20 ° C) circulation PU-ATO (3) the surface temperature of the composite textile. After B, application temperature of 40 ° C 8 hours per day (30 days in total), the surface temperature of the PU-ATO (3) composite textiles
