The Study Of Synthesis Of A Phosphonate Ester And Its Flame Retardancy In Thermoplastic Polyester Elastomer (TPEE)

The phosphonate esters are ones of important parts of organophosphorous flame retardants, some of them are free-halogen, high flame retardancy effectivity, low smoke and low toxicity to human beings, which accord with the tidal current of flame retardants. A novel flame retardant of phosphonate ester was synthesized and characterized by elementary analysis, FTIR, ~1H-NMR, GC-MS and thermogravimetric in this thesis. The phosphonate ester named by IUPAC is 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5] undecane, 3,9-dimethyl-, 3,9-dioxide(DMDP).Some factors affecting the reaction, such as reaction temperature and time, catalysts, the ratio of reaction materials were investigated. The results showed that the reaction speed is very rapid and the side reaction is little during 150℃～170℃.TG results under pure nitrogen showed that the weight loss was less than 2 percent at 260℃, and showed that DMDP had higher thermal stability.The application of the flame retardants combined with DMDP and melamine cyanurate (MCA) were investigated, comparing with PEPA (1 -oxo-4-hydroxymethy 1 -2,6,7-trioxa-1 -phosphabicyclooctane) and bromine-based flame retardants in TPEE resin. A series of flame retardant TPEE blends (FR-TPEE) were manufactured and experiment data were obtained by means of some instruments such as a tensile machine, limit oxygen index instrument, thermogravimetry and so on. The studies clearly showed that the compound of DMDP and MCA had a higher efficiency; Horizontal burning test reached FV-1 with higher mechanical performance, when the compound ratio of DMDP and MCA at 3:2, the flame retardant content was 15%, LOI of the FR-TPEE had reached 34.2% and tensile strength was 15.45MPa,yield strength was 14.02 MPa.The mechanism of the flame retardancy and thermal degradation performance of DMDP/MCA flame retarded TPEE was studied by means of TGA and Py-GC-MS. The TG results illustrated the residual ratio of FR-TPEE was 10.60% at 600°C,but the pure TPEE’s was only 4.12% at the same temperature, so DMDP had accelerated char formation . The initial degradation temperature of FR-TPEE was reduced, and the author consider that the phenomenon was the result of DMDP decomposition before TPEE, and char formation promotion, the char layer of the surface of flame retarded TPEE can restrain air and heat conduction, and further resist or delay the degradation of TPEE. The Py-GC-MS results also showed that DMDP had promoted char information.The kinetics of the thermal oxidative degradation of DMDP/MCA flame retarded TPEE blends were investigated by non-isothermal thermogravimetric analysis. Kissinger method, Flynn-Wall-Ozawa method had been used to calculate the activation energies of TPEE and FR-TPEE degradation, and the values were 202.88kJ/mol, 197.45kJ/mol (Kissinger method) , respectively. The results showed that DMDP had a little influence on the thermal stability of FR-TPEE.