| Polyester fabric is widely used for its excellent performance, while its limitingoxygen index (LOI) is about21%. Polyester fiber belongs to the combustible fiber,will be melt dripping phenomenon in the combustion process. Therefore, it isnecessary for the flame retardant finishing.In this paper, a new type of organic phosphorus flame retardant intermediate10-(2,5-Dihydroxyphenyl)-10H-9-oxa-10-phospha-phenantbrene-10-oxide(DOPO-BQ) and isophorone diisocyanate (IPDI), polyether glycols N210react toprepare environment-friendly flame retardant polyurethane. Then it applied to thecoating finishing on polyester fabric. We research the flame retardancy and thermalstability of polyester fabric and analyze the thermal degradation kinetics.We first synthesized fire-retardant aqueous polyurethane, and analyze thestructure of the products by Fourier transform infrared spectroscopy. It is found thatisocyanate groups disappeared in the infrared spectrum, and the emergence of the C=Pkey, P=O key,-NHCO-showed that the intermediates involved in the reaction, and weobtained the anticipated products. The optimum synthesis conditions were: thepolymerization temperature was70℃,3h; chain extension reaction temperature is70℃, dosage of catalyst DBTDL is0.5%, time4h; isocyanate index is3, and thecontent of DMPA is5.5%.The flame resistant waterborne polyurethane is applied on the polyester fabric.Vertical burning method is taken to test flame retardant performance of fabric, thenoptimize coating finishing, we get the best process for coating thickness is0.08mm,the curing temperature is170℃, after flame retardant finishing flame retardant effectof fabric can reach grade B1national level, the flame retardant effect of fabric afterwashing30times can still achieve level B2national level. It shows good washing fastness and anti-dripping performance significantly.Thermogravimetric analysis found that the initial decomposition temperature ofthe flame retardant fabric is in advance, and decomposition temperature range becamelarge. The maximum decomposition rate of the thin fabric decreased by58.74%,while the thick fabric decreased by35.21%. It enhanced the thermal stability of fabric.The cone calorimeter test shows that: TTI of the thin fabric extends from39s to101s,TTI of thick fabric extends from39s to75s, it greatly prolong the ignition time offabric; pkHRR of thin fabric decreased by30.5%, pkHRR of thick fabric decreased by39.3%; the results show that the fabric after flame retardant finishing the ignition timeand heat release rate decreased, the combustion properties and fire hazard of fabricreduced. Morphology characterization showed that residual carbon surface of thepolyester fabric after the combustion is continuous, uniform, smooth and compact,while carbon residue of untreated fabric has many small holes, insulated oxygen.Thermal stability of the fabric are greatly improved.Three kinds of models Flynn-Wall-Ozawa method, Friedman method andKissinger method were taken to study the thermal degradation process of polyesterfabric. The results found that the linear correlation coefficient of Kissinger methodwas above0.99, linear correlation is good. Activation energy of untreated polyesterfabric is175.52KJ/mol, the activation energy increased significantly, reaching199.26KJ/mol, the activation energy increased by13.7%. The average activationenergy of untreated fabric is216.95kJ/mol by Flynn-Wall-Ozawa method, and thetreated fabric is241.45kJ/mol, E value is more close to the result of Kissinger method.The average activation energy of untreated fabric is144.53kJ/mol by Friedmanmethod, and the treated fabric is173.39kJ/mol. The results of the three methodsshowed that the treated polyester fabric is not easy to thermal degradation; it has goodthermal stability. |
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