Effect Of Halogen-free Nitrogen-phosphorus Flame Retardant On TPEE And Synthesis And Properties Of Polyurethane Based Azo Dyes

Thermoplastic polyester elastomer(TPEE)is a type of block linear copolymer containing a polyester hard segment and an aliphatic polyester or a polyether soft segment.TPEE has excellent mechanical strength,excellent resilience,and a wide range of service temperatures.It is a thermoplastic elastomer with excellent overall performance.However,TPEE is a kind of flammable material,the limit oxygen index(LOI)is only about 20%.It is easy to ignite and burn quickly,which greatly limits its application.It is important to modify the flame retardant properties of TPEE.Polyurethane is a new organic polymer material,which has been widely used in many fields.Waterborne polyurethane has been developed more rapidly and applied more widely due to its excellent environmental performance and outstanding mechanical properties.However,currently there are few kinds of colored waterborne polyurethane,and the colored waterborne polyurethane prepared by physical blending have poor color stability and are easily affected by the external environment,and the color is not bright enough.In this paper,a variety of different small-molecule azo dyes were selected,and they were successively grafted into polyurethane chains by a stepwise polymerization method,the solvent type polyurethane-based azo dyes and waterborne polyurethane-based azo dyes have been synthesized.The main work of the dissertation is as follows:a)Synthesis and Properties of Phosphorus-nitrogen Halogen-free Flame Retardant TPEE cables:In order to improve the flame retardant properties of thermoplastic polyester elastomer(TPEE),the thermoplastic polyester elastomer with good flame retardancy was prepared by using phosphorus-nitrogen halogen-free flame retardants.The results show that the flame retardancy and thermal properties of TPEE were significantly improved.The flame retardant effect of melamine phosphate is the best among them,and oxygen index could reach 30%,vertical combustion level was UL-94 V-0,ignition time is 341 s,the peak heat release rate reached 134 KW/m2 at 355 s and the total release heat was minimal.Electrical performance studies have shown that because of the addition of flame retardants,not only suppressed the polarization and energy loss of TPEE polar groups,and the dielectric constant of TPEE was reduced,but also the insulation performance was improved.It is indicated that the addition of nitrogen-phosphorus halogen-free flame retardants has great influence on the properties of thermoplastic polyester elastomer.b)Synthesis and properties of solvent-based polyurethane azo dye:The solvent polyurethane was synthesized by stepwise polymerization method,in which MDI and PTMG(1000)were selected as the main synthetic raw materials,small molecule azo dyes were disperse diazo black GNN as chain extender.The structure was also confirmed by Fourier transform infrared spectroscopy.The solvent-borne polyurethane group was characterized by UV-visible absorption spectroscopy,TG,DSC,and tensile strength at break.The experimental results show that the solvent-borne polyurethane is a semi-crystalline structure with good thermal stability and its fracture Tensile strength is high.The most important is that the polyurethane dispersion prepared by this method not only has good stability and does not fade easily,but also has good photochromic properties.Under the irradiation of ultraviolet light,The absorbance and color of the polyurethane dispersion have been changed significantly.The photochromic properties of the polyurethane-based azo dye broaden the field for polyurethane applications.c)Synthesis and properties of water-based polyurethane azo dye:The water-based polyurethane azo dye was synthesized by stepwise polymerization method,in which IPDI and PTMG(1000)were selected as the main synthetic materials,DMPA as hydrophilic chain extender,small molecule azo dye(dispersed black 3BF or Sudan Orange G)as color chain extender,Triethylamine as salt-forming agent and deionized water as dispersion.The structure of the waterborne polyurethane azo dye was confirmed by FTIR.And other tests were performed on waterborne polyurethane azo dye,such as UV-Vis absorption spectroscopy,fluorescence spectroscopy,TG and DSC,etc.The results show that the thermal stability of the waterborne polyurethane cured film is very well.Its dispersion has a strong fluorescence intensity and good photochromic properties.The color stability of the dispersion is also very well.