Synthesis And Characterization Of Phosphorus Flame Retardant Polyurethane Elastomers

Polyurethane elastomers (TPU) are called "The second generation rubber", because they not only have the high elasticity like rubber, but also have the stiffness like plastic; they have been widely applied in the aerospace, medical treatment, sports, life and other areas. People requirement to materials increase with the development of society, especially the flame resistance of materials. Phosphorus compound was introduced in polyurethane elastomer to enhance its flame retardancy and not polluting environment at the same time.In this study, two kinds of different phosphorus compounds were synthesized, and used in polyurethane elastomer respectively. The performances of PPUEs were also invesitgated.(1)Two species of phosphorus diamines Bis (4-aminophenoxy) phenyl phosphine Oxide and diamines phenyl phosphine Oxide were synthesiszed based on phenyl phosphonic dichloride. It was characterized by Fourier transform infrared spectroscopy (FTIR) and1H NMR and31P NMR. The above characterizations are in good agreement with the chemical structure of BAPPO and DAPOP.(2) A series of phosphorus polyurethane elastomers were prepared based on BAPPO and DAPOP by changing the molecular weight polymer polyols. The structures and properties of PPUEs were analyzed with the measurements of FTIR, MCC, TGA, tensile tests and SEM. The FTIR of phosphorus polyurethane elastomers showed that phosphorus-containing diamine completely reacted with polyurethane prepolymers. The phosphorus containing polyurethane had good flame retardancy that was improved along with the phosphorus content increasing. Thermal stability of Phosphorus polyurethane elastomer increased with the molecular weight of soft segments increasing.The char yield of phosphorus polyurethane were higher than that of general polyurethane, and the SEM photos indicated that the residual carbon surface was more compact, which can protected the polymer surface.(3)Phosphorous oligomers (PFR) were synthesiszed based on Phenyl phosphonic dichloride and Bisphenol A2-chlorobenzotrifluoride. It was characterized by FTIR and1H NMR,19F NMR and31P NMR. The above characterizations were in good agreement with the chemical structure of Phosphorous oligomers.(4) A series of phosphorus polyurethane elastomers were prepared based on APP and PFR, and there properties were characterized. The results showed that the decomposition temperatures of polyurethane elastomers which based on APP and PFR were down, but the char yield of phosphorus polyurethane increased. They char were more than25%. The PHRR of polyurethane elastomers based on PFR decreased significantly which were lower59.26%compared with the polyurethane elastomers based on APP. The LOI of polyurethane elastomers which based on30%APP or PFR were reached29, showing good flame retardant effect. The viscous flow activation energy of polyurethane elastomers based on APP was increased compared with the pure polyurethane elastomers, but the viscous flow activation energy of polyurethane elastomers based on PFR was down.(5) Thermodynamic decomposition of polyurethane elastomers were studied by thermogravimetry, and the activation energy of pyrolysis were calculated by Kissinger’s methods. The pyrolysis of polyurethane elastomers is divided into two stages. The activation energy of PPUE-1is lower than that of PUE in the first stage, but higher in the second stage. Figure33; table18; reference62...