Study On The Recycle And Reuse Of Polyurethane Fiber Wastes

Polyurethane fibers are prepared by spinning with urethane-based material. Owing to its excellent elasticity and mechanical properties, polyurethane fibers have shown considerable applications in the areas of textile and clothing industry. The quantity of the dry-spinning polyurethane fiber reached about 200,000 tons in 2004. As a most economic and environment friendly method, melt-spinning polyurethane fiber has developed rapidly. With the rapid development of the polyurethane fiber industry, however, it produces a large amount of wastes during the process of preparation and application. At present the waste has been treated mainly by landfilling or incineration, which causes environmental pollution and resource loss. Therefore, reasonable methods for recycle of polyurethane fiber wastes have becoming an urgent task to be solved for the manufacturers.In this paper, the glycolysis of dry-spinning polyurethane fiber waste with diethylene glycol has been studied. The recycled Polytetrahydrofuran (PTMG) can be obtained from the glycolysis product. By measuring the intrinsic viscosity of the glycolysis products with reaction time, the glycolysis kinetics has been analysed. The activation energy of the glycolysis is 129.37kJ/mol. The influences of reaction conditions such as reaction time, reaction temperature, ratios of reactants, etc on the purity of the recycled PTMG are discussed by FTIR measurements. It has been shown that the purity of the recycled PTMG increases with the increasing of the content of glycolysis agent and catalyst. By using the recycled PTMG, polyurethane film has been synthesized. However, the mechanical property of the film is poorer than that synthesized from pure PTMG.Melt-spinning polyurethane fiber waste has been thermo-degraded in triethylene phosphonate by adding acetamide. The influences of reaction time and reaction temperature on the degree of degradation have been studied. The results show that themelt-spinning polyurethane fiber waste can obtain the re-process ability by this method. The proper thermo- degradation condition is 170°C, 30min. The recycled polyurethane film has been synthesized by mixing the degraded product with fresh PTMG and then reacting with TDI. The tensile strength of the recycled polyurethane film is about 2-4 times higher than that of the degraded product. The initial weight loss of the recycled film is about 220 °C. With the increasing of degraded product content, the temperatures of the initial weight loss decrease. The apparent activation energy of thermo- degradation is about 34kJ/mol.