Synthesis And Study On The Properties Of Novel Phosphorous-nitrogen-containing Flame Retardants

The high standard of living enjoyed by the citizens of developed nations of the worldwould not be possible without the development of polymeric materials which has occurredwith the development of the petroleum industry since WWП. Unfortunately, a majorproblem appears as most of the polymers are organic inherent and thus flammable. Theflammability limited their uses. So there are greatly sociological, legislative and economicpressures on the polymer industries to produce flame retardant materials. It has been widelyrecognized that it is a useful way to produce high–performance flame retardant polymers byadding flame retardants into these materials. Many flame retardant additives have beenresearched to give flame–resistance to polymers. Traditionally, halogenated organiccompounds with good flame–resistant characteristics have been widely used in polymers,especially combined with antimony. However, the application of halogen–containingmaterials in the polymers leads to environmental problems。Thus, tremendous efforts havebeen made by the researchers to find halogen–free flame retardants. Among them, organicphosphorus compounds are well known to be potential candidates that can replace thehalogen–based flame retardants. The advantage of phosphorus–containing compounds isenvironmental friendliness as they are believed to produce less toxic gases and smoke thanhalogen–containing compounds, so it is meaningful to develop new phosphorus–containingflame retardants.Various methods such as extrusion, injection molding, coating, solution casting and so onare applied to prepare the flame retardant polymer materials by blending the additive flameretardants with the polymers. Among all of the methods, solution casting plays an importantrole in the material processing as it is an economic and convenient processing method thatcan mix the flame retardants with polymers homogeneously and thus avoid the migration ofinsoluble flame retardant from the materials and the uneven distribution of the insolubleflame retardants in the materials which can result in a decrease of the mechanical strengthand the increase of the brittleness of the materials. So looking for a proper solvent todissolve the flame retardant is helpful for the use in the polymers by the method of solution casting.The (solid+liquid) equilibrium (SLE) measurements of PNBE with organic solventsnot only are useful for the fundamental data for the characteristics of products but alsosupply the database for assessing the applications and limitations of the continueddevelopment of solution models established for describing the thermodynamic properties.For these reasons, the main contents of this dissertation are summarized as follows:PAPBE、PNBTE、PNBE、CPADE、PANDE、PAETE were synthesized and characterizedby elemental analysis (EA), mass spectra (MS), infrared spectroscopy (IR) and nuclearmagnetic resonance (NMR). The melting point and the enthalpy of fusion of the sixcompounds were obtained by differential scanning calorimeter (DSC), and the thermalstability of the six compounds was measured by thermogravimetric analysis (TGA).PBPA hydrochloride was synthesized by using a typical Mannich reaction. As it hardlydissolve the common solvents. Reaction of the aminophosphinic acid with CdCl2, CoCl2,ZnCl2, CuCl2, H2SO4and HClO4in concentrated hydrochloric acid yielded some crystalproductions, which characterised by single–crystal diffraction. And the structures werefirstly reported in this work.DMOE and DDMO was prepared by reaction of DOPC with ethylenediamine and2,4,6–tribromophenol. The structure of the target compound was characterized by elementalanalysis (EA), infrared spectroscopy (IR), mass spectrum (MS) as well as nuclear magneticresonance (1H NMR and13C NMR) and its spectral properties were discussed. Its meltingpoint, melting enthalpy and thermal stability were studied by differential scanningcalorimeter (DSC) and thermogravimetric analysis (TGA).DMOE and DDMO were synthesized and characterized by elemental analysis (EA),mass spectra (MS), infrared spectroscopy (IR) and nuclear magnetic resonance (NMR). Themelting point and the enthalpy of fusion of the six compounds were obtained by differentialscanning calorimeter (DSC), and the thermal stability of the six compounds was measuredby thermogravimetric analysis (TGA).Solid–liquid equilibrium for organic phosphorus flame retardants PAPBE、PNBTE、PNBE、CPADE、PANDE、PAETE DMOE and DDMO were studied. The solubilities ofeight laboratory–made organic phosphorus flame retardants in selected solvents were measured by a static analytical method. The solubilities data of PAPBE、PNBTE、PNBE、CPADE、PANDE、PAETE DMOE and DDMO in the selected organic solvents weredetermined for the first time. The results were as following:At a given low temperature, the order of solubility of PNBTE is as follows: acetonitrile>tertrahydrofuran> acetone> methyl acetate> methanol> ethyl acetate>dichloromethane> ethanol> chloroform> toluene, but in high temperature the orderchanged to be tertrahydrofuran> acetonitrile> acetone> methyl acetate> toluene> ethylacetate> methanol> chloroform> ethanol.At a given temperature, the solubility order of PNBE is tetrahydrofuran> chloroform>dichloromethane> acetone> methanol> ethanol> ethyl acetate> acetonitrile> benzene>toluene.At a given temperature, the order of solubility of PAPBE is as follows: chloroform>dichloromethane> benzene> tetrahydrofuran> ethylacetate> toluene> ethanol>acetone> methanol.At a given temperature, the order of solubility of CPADE is as follows: chloroform>tertrahydrofuran> dichloromethane> benzene> toluene> acetone> methanol> ethanol>ethyl acetate> acetonitrile.The solubilities of PANDE in different solvents at low temperature are in the order ofchloroform> tetrahydrofuran> dichloromethane> acetone> methyl acetate> ethylacetate> acetonitrile> methanol≈toluene, but at high temperature are in the order ofchloroform> tetrahydrofuran> dichloromethane> acetone> methyl acetate> ethylacetate> methanol> toluene> acetonitrile.At a given high temperature, the order of solubility of PAETE is as follows:chloroform> tertrahydrofuran> methanol> acetone> ethanol> ethyl acetate> methylacetate> acetonitrile> benzene> toluene, but at low temperature the order changed to bechloroform> tertrahydrofuran> acetonitrile> ethyl acetate> acetone≈methyl acetate≈methanol≈ethanol> benzene> toluene.The order of the mole fraction solubility of DMOE in selected solvents at aconstanttemperature is butanone> diethyl ether> ethyl formate> tetrahydrofuran> methanol>isopropanol>1,2–dichloroethane> acetonitrile. The solubility order of DDMO in the select solvents at mosttemperatures is ranked astrichloromethane> dichloromethane> tetrahydrofuran> acetone> toluene> methylacetate> acetonitrile> ethyl acetate> ethanol> methanol.The solubility data of PAPBE、PNBTE、PNBE、CPADE、PANDE、PAETE DMOE andDDMO at different temperatures in selected solvents were correlated with λh equation,Wilson, UNIQUACand NRTL thermodynamic model. The results showed that thecalculated values were in good agreement with the experimental data and the relativestandard deviations of most binary systems were less than2%. The solubility parameter ofthe eight compounds were estimated by the Scatchard–Hildebrand Model, meanwhile thedissolution enthalpy, and entropy in the selected solvents were also calculated by the Van’tHoff equation and Gibbs–helmoholtz equation.PNBTE and PNBE were used in epoxy resins as flame retardants. The retardantproperties were studied. The results show that PNBTE and PNBE are the good flameretardants for the epoxy resins. Both of them worked in condensed phase and gas phase butthey dominated by the condensed phase mechanism.