Study On Phosphorus-Containing Flame Retardent Thermoplastic Polyester Elastomer

Thermoplastic polyester elastomer（TPEE）consists of hard and soft segments,therefore it has high performance with respect to physical and chemical properties.As its application abroad,fire resistance property is more and more requested.2-Carboxyl ethyl（phenyl）phosphinic acid （CEPPA）is a copolymerizable phosphorus monomer,it can be polycondensed with dimethyl（DMT）,1,4-butanediol（BD）, poly（tetramethylene glycol）（PTMG;Mn=1000）to produce flame retardant thermoplastic polyester elastomer（FR-TPEE）.The structures and properties,such as crystallization property,dynamic rheology property,thermodegradation kinetics and thermodegradation mechanism, flame retardant and mechanical property etc were investigated by FT-IR, NMR,XRD,DSC,PLM etc.The result are as follows;1.The addition of chain-extension reagent was usefull to synthesis high performance copolymer.The result of FT-IR spectra showed that the new absorption band at 935cm^-1was indicative of appearance of the（P-O-C）.The result of ³¹P NMR and ¹H NMR FT-IR spectra showed that the flame retardant connected with the macromolecule after add the flame retardant. 2Most of the flame retardant connected with the macromolecule which were located in the amorphism region.The location of diffraction peak 28 changed after the addition of CEPPA.The result of PLM and crystal particle measurement by XRD showed that the crystal of FR-TPEE decreased.The result of DSC showed that the melting point of solft and hard segmend and the crystallinety of hard segment decreased, but the crystallinety degrees of solft segment increased after added the flame retardant.3The result of dynamic rheology showed that the melt of TPEE and FR-TPEE was viscoelasticity liquid.Their melt was micro phase separation in the test range and the forms of phase changed with the temperature and the frequency.G,G",η’ and tanδchanged with the transformation of melt structure in the different law.Also the dependence of logG’- logG" curve to temperature increased after addition of CEPPA.4.The result of thermodegradation kinetics showed that the degradation of TPEE and FR-TPEE had three stages.The activity energy of FR-TPEE was lower than that of TPEE in the stage one,but the activity energy of FR-TPEE was higher than the activity energy of TPEE in the stage two.The thermodegradation mechanism in the stage one was Phase boundary controlled reaction and One-dimensional diffusion mechanism in stage two of all the samples.The flame retardant did not change the mechanism of degradation of TPEE.5.The result of IR-TG showed that the flame retardant in FR-TPEE was easy to break out of the FR-TPEE molecule,then the flame retardant molecule decomposed into PO free radical and other flame retardant substance which could prevent the other substance that decomposed from the copolymer burning.6The result of uprightness combustion method and the test of oxygen index showed that the fire resistance property of FR-TPEE achieved the operating requirement and the limited oxygen index achieved the national standard（LOI）>28.7The result of DMA showed that the TPEE and FR-TPEE were micro phase separation.There were two Tg in every test range of the samples,and the addition of CEPPA promoted the micro phase separation. The result of stretching test showed that the elastic deformation of TPEE and FR-TPEE had no obvious difference.The yield stress of FR-TPEE was higher than that of TPEE.The plastic deformation,breaking strength and elastic property of FR-TPEE became lower,but the elastic property of FR-TPEE achieved the operating requirement.