Preparation And Characterization Of Fluorinated Polyurethane Elastomers

Due to their excellent mechanical and processing propertites and other advantages, polyurethane elastomers(PUE) have been widely appilied in our daily lives and many other fields. However, with the development of science and people's higher and newer requirements. Riginal PUE materials have shown insufficiency and their use has been limited. Fluorinated Polyurethane Elastomers(FPUE), as a species of novel functional macromolecule materials, owing to the introduction of fluorinate, have excellent surface properties, excellent resistance to chemicals and other unique qualities. So FPUE have mitigated the above mentioned shortages of PUE.In this study, two species of aromatic fluorinated diamines were synthesized and two diamines were used as chain extender to prepare a series of fluorine containing polyurethane elastomers(FPUEs) with different fluorine contents. The structure and properties were measured.(1) Two species of aromatic fluorinated diamines 1,4-bis(4-amino-2-trifluofometh-yloxyphenyl)benzene(BAFB) and 2,2-bis[4-(4-amino-2-trifluoromehyloxyphenyl) phen-yl]propane(BAFPP), were synthesiszed based on 2-chlorobenzotrifluoride, p-dihydroxy-benzene and Bisphenol A. Their structure and properties were determined by FTIR, NMR(1H-NMR,19F-NMR). The results showed that the structure of BAFB and BAFPP met our expectation.(2) Preparation of fluorine-containing polyurethane elastomers(FPUE-â… , FPUE-â…¡) chain extended by BAFB and BAFPP.FPUE(FPUE-â… , FPUE-â…¡)were prepared with the chain extender(BAFB and BAFPP) and polyurethane prepolymers, which prepared with TDI, DDL, PTMEG2000 and polyester2000. FPUE were prepared by a two-step method. In the first step, isocyano-capped polyurethane prepolymers were synthesized with isocyano index 2, and in the second step, the prepolymers and chain extender were dissolved in a certain amount of solvent, and then mixed two parts are mixed to prepare FPUE. At the same time, PUE with the conventional chain-extender MOCA was prepared to be compared with the new elastomers.The structures and properties of FPUEs were analyzed with the measurements of FTIR, contact angle measurement, XPS, TGA, MCC and tensile tests. The results showed that fluorine was successfully incorporated into the polyurethane chains whose terminal group is-NCO with BAFB and BAFPP reacting to prepolymers. FPUE showed a good hydrophobic property and lower surface tension due to the introduction of fluorine and its increase on the air-side of the surface for materials. At the same time these polymers exhibited good thermal stability, good flammability properties and mechanical properties.(3) The curing kinetics of PUE and FPUE was prepared with MOCA and BAFPP as chain extender was assessed.Isothemal curing curves of polyurethane elastomers were made by the dynamic torsional vibration method, in which prepolymer of PTMEG-2000 was the first components and the chain extender(MOCA and BAFPP) was the second components. Apparent activation energy Ea and reaction rate constant k were calculated. The results showed that the Ea of prepolymer/BAFPP is lower than the prepolymer/MOCA. Simultaneously, the crosslinking reaction of polypolmer/BAFPP is a first order reaction, which is the same as the crosslinking reaction of polypolmer/MOCA. Figure 39; table 22; reference 55;...