Synthesis Of DOPO Derivatives And Study On Properties Of Flame Retardant Flexible Polyurethane Foam

This paper introduces the basic characteristics and combustion process of flexible polyurethane foam(FPUF),and summarizes the research status and progress of flame retardant FPUF.Based on the disadvantages of FPUF that is easy to burn and easily produces-toxic gases during combustion,this paper takes 9,10-dihydro-9-oxa-10-oxaphenanthrene-10 oxide(DOPO)as the starting point and a variety of DOPO-based derivatives were synthesized.The effects of DOPO derivatives on the physical structure,mechanical properties,thermal stability and flame retardancy of FPUF were studied,and it was revealed that DOPO derivatives can promote the formation of carbon crosslinking networks and quench the active free radicals in flames.In order to further reduce the flue gas production and flue gas toxicity,a novel metal-organic framework compound(Sn-MOF)was synthesized based on the catalytic effect of metal elements to form carbon.Combined with the highly efficient DOPO-based flame retardant that has been synthesized,the performance of smoke suppression and toxicity reduction of Sn-MOF nanocomposite was studied.The specific research content is as follows:1.The DOPO derivative salts of phosphorus-nitrogen synergistic flame retardant system were prepared by hydrothermal reaction method and FPUF composites were prepared.The effect of DOPO derivative salts on the comprehensive performance of FPUF was systematically studied.The results show that the addition of DOPO derivative salts can increase the limiting oxygen index of FPUF composites,extend the ignition time of the foam,and reduce the heat release during foam combustion.Among them,10-hydroxy-9,10-dihydro-9-oxa-10-phosphorphenanthrene-10-oxide-dicyandiamide salt(D-DICY)exhibits the best flame retardant performance.When its addition amount is 20 parts,the limiting oxygen index of the flame-retardant foam composite increased to 24.5%,and the peak heat release rate and total heat release decreased by 56%and 53%,respectively.By analyzing the products in the combustion process,a possible flame retardant mechanism is proposed.2.A high molecular weight flame retardant polyester DIDG containing DOPO derivatives was prepared by polycondensation and flame retardant FPUF composites were prepared.The research results show that with the increase of DIDG addition,the flame retardant performance of FPUF has gradually improved.When the amount of DIDG added is only 5 parts,the foam can pass the vertical burning test with TB 117-2000 as the standard.When the amount of DIDG added is 20 parts,the oxygen index of the foam can reach 23.5%.At the same time,the introduction of DIDG does not affect the foaming process of FPUF,and it can be well dispersed into the polyurethane matrix to improve the tensile strength and indentation hardness of the foam.When the addition of DIDG is 20 parts,the tensile strength and 25%indentation hardness of the foam are increased by 35%and 56%,respectively.3.A novel Sn-based metal organic framework compound(Sn-MOF)was designed and prepared,and flame-retardant FPUF composites were prepared by combining the synthesized D-DICY.The results show that the introduction of Sn-MOF can further improve the flame retardant performance of FPUF.When the amount of Sn-MOF added is 3 parts,the limiting oxygen index of FPUF reaches 25.5%,the heat release rate decreases by 18%,and the residual carbon rate increases to 11%.At the same time,the addition of Sn-MOF can significantly reduce the flue gas production of FPUF and inhibit the release of toxic gases.When the amount of Sn-MOF added is 3 parts,the total flue gas emission during the combustion of the foam is reduced by 17%,and the intensity of infrared absorption peaks of toxic and harmful gases such as CO,CO2 and HCHO gas are significantly reduced.After a systematic analysis of the combustion products,the flame retardant and smoke suppression mechanism of Sn-MOF was proposed.