Synthesis And Characterization Of Functional Polyurethane Elastomers

Polyurethane elastomer(PUE) is a block copolymer which is composed of soft segments and hard segments. PUEs show excellent performance such as high strength, good toughness, ideal wear resistance and oil resistance resulting from their molecular design. PUEs are called "wear rubber" as they have not only the high elasticity like rubber but also the stiffness like plastic; moreover, there is a variety of processing methods with polyurethane elastomers. Due to these advantages, PUEs have been widely applied in industry, medical treatment, life products and some other fields. However, some drawbacks of PUEs such as hydrolysis and flammability restrict its application. Novel PUEs show better comprehensive performance with the introduction of functional element. Fluorine containing polyurethane elastomers (FPUEs) show excellent surface properties, chemical stability, etc with the introduction of fluorine; phosphorus containing polyurethane elastomers (PPUEs) show better flame retardancy with the introduction of phosphorus. In this study, two novel chain extenders:fluorine containing diamine and phosphorus containing diamine were synthesized, and they were used to prepare a series of FPUEs and PPUEs, respectively. The performances of FPUEs and PPUEs were also invesitgate.(1)2-trifluoromethyl-4,4’-diaminodiphenyl ether (TDAP), a novel fluorine containing aromatic diamine was derived from2-chlorobenzotrifluoride and p-nitrophenol. The chemical structures of TDAP were identified by FTIR,1H NMR and19F NMR. The above characterizations are in good agreement with the chemical structure ofTDAP.(2) FPUEs were made based on TDAP, poly(tetramethylene ether glycol)(PTMEG) and toluene diisocyanate (TDI). A series of FPUEs which contain different ratios of hard segments and soft segments were prepared by changing the diisocyanate index and the molecular weight of the soft segment. The contact angle, of FPUEs prepared from TDAP was larger, and the water absorption of FPUEs was much lower than PUEs which were based on MOCA. This suggests that FPUEs have a lower surface tension and a better hydrophobic property; and the lower surface tension and better hydrophobic property become more pronounced with the increasing of the fluorine content. FPUEs also show better thermal stability than PUEs. Additionnally, they show good flame retardancy and mechanical properties.(3) Phenyl diaminophosphate(PDAP), a novel phosphorus containing aromatic diamine was synthesized in one step. The chemical structures of PDAP were identified by FTIR,1H NMR and31P NMR. The above characterizations are in good agreement with the chemical structure of PDAP.(4) PPUEs were made based on PDAP, polyester diols and TDI. A series of PPUEs which contained different ratios of hard segments and soft segments were prepared by changing the diisocyanate index and the molecular weight of the soft segment. The initial decomposition temperatures was lower than PUEs which were made from MOCA. The the char yield of PPUEs are much higher than that of PUEs, the char yield of PPUE-1whose soft segment monomer was1213g/mol(Phosphorus content at1.6%) reached35%, and the SEM result showed that the residual carbon surface was more compact.(5) Thermodynamic decomposition of FPUE, PPUE and PUE were studied by thermogravimetry, and the activation energy of pyrolysis was calculated by integral and differential methods. Between the FPUE and PUE whose soft segments are all PTMEG, the DTG curve of FPUE is different from the DTG of PUE base on MOCA. Between the PPUE and PUE whose soft segments are all polyester diols, the pyrolysis of both is divided into two stages. The activation energy is lower in the first stage, but higher in the second stage.Figure32; table15; reference58;...