Synthesis And Study On The Themophysical Properties Of New Phosphorus-containing Flame Retardant

Polymeric materials have become widely used for many different applications;however, most of them are inherently combustible and, in the presence of a heat source,will burn easily and quickly. In order to prepare good thermal stability materials, the mostcommon method is to add flame retardant (FR) additives into polymeric materials. Thephosphorus-containing flame retardant has wide development potential owning to highflame retardant efficiency, low toxicity, low corrosion and good compatibility with polymermaterial. In the phosphorus-containing compounds, cyclic phosphates and its derivativesbased on neopentyl glycol have excellent thermal stability and a rich source of carbon andacid, and thus they can widely be used in the field of the flame retardant and have a goodprospect.The study on their thermal stability and melting point by thermogravimetric analysis(TGA) and differential scanning calorimetry (DSC) is very important for selecting andmatching the suitable flame retardants for engineering plastics based on the processingcharacteristics. Data of solubility plays a very important role for selecting the solventduring the synthesis process for flame retardant, and a suitable solvent should not onlyrestrain the generation of by-products, but also be benefit for the target products and makethe product easy separation and purification. In addition, flame retardant compounds withlower purity are often with poor thermal stability, less compatible with the material andlower flame-retardant efficiency. Therefore, the systematic and complete data of solubilitycould be provided the important basis for selecting the solvent in the process of synthesisand purification of flame retardant, and for calculation of the solid-liquid equilibrium. Forthese reasons, the main contents of this dissertation are summarized as follows:Three cyclic phosphate derivatives based on neopentyl glycol: bisphenol A-bis(5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy phosphate ester)(BADOPE), bisphenolS-bis (5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy phosphate ester)(BSDOPE) andtetra(5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy) neopentane (DOPNP) were prepared bybisphenol A, bisphenol S and pentaerythritol respectively. The structures of these compounds were characterized by elemental analysis (EA), infrared spectroscopy (FT-IR),as well as nuclear magnetic resonance (1H NMR and31P NMR) and their spectral propertieswere discussed. Their melting point, melting enthalpy and thermal stability were studied bydifferential scanning calorimeter (DSC) and thermogravimetric analysis (TGA).The flame retardant DOPNP was prepared with N-methyl-N-allyl-morpholinetrifluoromethanesulfonate ionic liquid as the solvent and acid-binding agent, and the resultwas compared with the experiment with traditional organic solvents as the reaction mediumand acid-binding agent in the preparation of the flame retardant. Besides, activitycoefficients at infinite dilution ifor23solutes in the ionic liquid1-hexyl-3-methylimidazolium trifluoroacetate ([HMIM][TFA]) were determined by gas-liquidchromatography. The measurements were carried out at different temperatures between303.15K and363.15K. The partial molar excess enthalpies at infinite dilution and thesolubility parameters of ionic liquid [HMIM][TFA] were also calculated from theexperimental values of activity coefficients at infinite dilution.A novel phosphorus-containing flame retardant with lower level of bromine,tetrabromobisphenol A-bis (5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy phosphate ester)(TBAPE), was firstly synthesized and characterized by elemental analysis (EA), massspectra (MS), infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR and31P NMR). Thermal degradation behaviors of TBAPE were studied using DSC and TGAtechniques. The kinetic parameters and the mechanism for its thermal degradation wereevaluated with the data processing performed by using several methods, includingKissinger method, Kissinger–Akahira–Sunose method (KAS method), Flynn-Wall-Ozawamethod (FWO method) and atava-esták method.The solubilities of BADOPE、BSDOPE and DOPNP in the select solvents weremeasured by static analytical method for the first time and included: the solubility data ofBADOPE in acetonitrile, acetone, methanol, tetrahydrofuran, ethanol, ethyl acetate,methylethylketone,1,4-dioxane, isopropanol and n-propanol; the solubility data ofBSDOPE in acetonitrile, acetone, methanol, tetrahydrofuran, ethyl acetate,trichloromethane, methylethylketone, toluene,1,4-dioxane and binary solvent mixture ofmethanol+trichloromethane and the solubility data of DOPNP in acetonitrile, acetone, methanol, ethanol, ethyl acetate, methyl acetate, methylethylketone, dichloromethane,tetrahydrofuran, trichloromethane, isopropanol,1,4-dioxane, and water. Furthermore, thetrends of solubility changes with temperature were studied, the experiment data werecorrelated with the ideal solution equation，and the value of activity coefficients werecalculated by the melting point and enthalpy measured by DSC. It provides a fundamentalthermodynamic property data for the purification and synthesis in the industry.The solubilities data of BADOPE, BSDOPE and DOPNP at different temperatures inselected solvents were correlated with the Apelblat, Wilson, NRTL, UNIQUAC and(NIBS)/Redlich-Kister model. The results showed that the calculated values were in goodagreement with the experimental data and the relative standard deviations of most binarysystems were less than3%. According to the Scatchard-Hildebrand activity coefficientmodel, solubility parameters of these compounds were calculated, and the effect oftemperature on the solubility parameter was discussed. The Scatchard-Hildebrand theorywas also used to explain the maximum-solubility effect of BSDOPE in the methanol+trichloromethane mixed solvent.