Preparation And Characterization Of Phosphorus Containing Waterborne Polyurethane

Waterborne polyurethane(WPU)has excellent stability,physical properties and environmentally friendly which widely used in various fields.WPU is a kind of polymer material which has the danger of flammability.The lack of excellent flame retardant properties will limit its use to a certain extent.The development,production and use of WPU with flame retardant properties have attracted more and more attention.In WPU,flame retardancy can be improved by introducing flame retardants components from chain segments or adding flame retardants through physical blending.With the progress of science and technology,it is becoming more and more important to seek environmental friendly and safety flame retardants.Among them,phosphorus-based flame retardants and inorganic flame retardants are used more and more as halogen-free flame retardants and become more and more mature,effectively overcoming the shortcomings of halogen-based flame retardants.In this paper,flame retardant WPU were prepared by physically blending phosphorus-containing(P)flame retardant cyclic phosphate(FR-1036)with WPU,copolymer chain extender which is modified by 9,10-dihydro-9-oxo-10-phosphenanthrene-10-oxide(DOPO),reaction of modified kaolin(KA)with phosphorous polycarbonate(BY3009T).The effects of different kinds of flame retardants and modification methods on the properties of waterborne polyurethane were studied.The main contents of this paper are as follows:(1)Preparation of flame retardant WPU by physical blending of FR-1036 flame retardant.Waterborne polyurethane(WPU)was synthesized with polyadipate-1,4-butanediol diol(PBA)and isophorone isocyanate(IPDI)as the main materials.Then the flame retardant waterborne polyurethane(WPUP)was prepared by physical blending of FR-1036 and WPU.The effects of FR-1036 content on WPU performance were studied by Fourier infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),limiting oxygen index(LOI),vertical combustion test(UL-94),cone calorimeter(CCT)and scanning electron microscope(SEM)tests.The results showed that with the increasing of FR-1036 content,the hardness and tensile strength of WPUP film decreased.When the FR-1036 mass fraction is 15%,the comprehensive performance of the flame retardant waterborne polyurethane is the best with the LOI of 27%which reached the flame retardant level.The UL-94 test showed the flame retardant performance of WPUP reached V-0 level.(2)Modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)as chain extender to prepare flame retardant WPU.In order to maintain a balance among flame retardancy,thermal stability and the mechanical properties of waterborne polyurethane(WPU),the reactive flame retardant(DOPODEA)containing phosphorus and nitrogen was synthesized in one step and introduced into polyurethane prepolymer to prepare a series of waterborne polyurethane materials(DWPU)modified by flame retardant chain extender.The effects of DOPODEA content on the flame retardancy of DWPU were studied by nuclear magnetic hydrogen spectroscopy(~1HNMR),Fourier infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),limiting oxygen index(LOI),vertical combustion test(UL-94),cone calorimeter(CCT)and scanning electron microscope(SEM).The test results showed that with the increasing of the content of flame retardant chain extender,the limit oxygen index(LOI)of the waterborne polyurethane increased from 19%to 33%,the flame retardant performance of the vertical combustion(UL-94)test has reached V-0 level.When the molar mass ratio of DOPODEA to 1,4-butanediol(BDO)is 1:1,the comprehensive performance of the flame retardant waterborne polyurethane(DWPU3)is the best.The cone calorimeter test showed that the peak heat release rate(PHRR)of DWPU3was decreased to 491.45 kW/m~2,the total heat release rate(THR)was reduced to 41.17 MJ/m~2which has a good flame retardant effect.(3)Flame retardant waterborne polyurethane(KBWPU)composite prepared by BY3009T and KA.A series of organic phosphorus flame retardant modified waterborne polyurethane(BWPU)were synthesized by polyadipate-1,4-butanediol diol(PBA),phosphorus-containing polycarbonate diol(BY3009T)and isophorone diisocyanate(IPDI)as the main raw materials.Then the modified kaolin(KA)was added to BWPU to prepare composite flame retardant waterborne polyurethane(KBWPU).The FTIR,thermogravimetric analysis(TGA),limiting oxygen index(LOI),vertical combustion test(UL-94),cone calorimeter(CCT)and scanning electron microscope(SEM)were used to study the effect of the different BY3008T and KA content on the performance of waterborne polyurethane.The results showed that when the BY3009T:PBA mass ratio was 20:20,the limiting oxygen index(LOI)of the flame retardant waterborne polyurethane(BWPU20)increased to 26%,the vertical combustion(UL-94)test reached to V-2 level.As the mass fraction of KA added to BWPU20 increased,the flame retardant performance improved.When the content of KA was 1.5%of the mass fraction of BWPU20(KBWPU20-1.5%),the flame retardant performance was the best with the LOI value of 30%.The flame retardant performance showed by the vertical combustion test has reached level V-0.