Study On The Heat Resistance Of Polyurethanes Elastomers

Two aromatic diamines, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (BAPF6P) and bis[4-(4-aminophenoxy)-phenyl]sulfone (BAPS), were synthesized with bis(4-hydroxylphenyl)sulfone, 2,2-bis(4-hydroxylphenyl)hexafluoropropane and 4-chloralnitrobenzene.The structures and chemical components of BAPF6P and BAPS were characterized by FTIR, 1H-NMR, EA. The results showed that the obtained diamines agreed with our expectation both in the structure and chemical components.1. Preparation of fluorine-containing polyurethane elastomers (FPUEs) chain-extended by BAPF6PFPUEs were prepared with TDI-100, PTMG and the chain extender, BAPF6P. FPUEs were prepared in a two-step method. In the first step, isocyano-capped polyurethane prepolymers were synthesized, and in the second step, the prepolymers were chain extended by BAPF6P to prepare FPUEs. During the preparation, a series of FPUEs with different weight content of hard segments: FPUE-1, FPUE-2 and FPUE-3 were prepared by changing the ratio between TDI and PTMG.PUE with the conventional chain-extender MOCA was prepared to be compared with the new elastomers.The morphologies and properties of FPUEs were analyzed with the measurements of FTIR, WAXD, AFM, TGA, DMA and tensile tests. The results showed that the degree of microphase separation was high; the heat resistance and mechanical properties were excellent because of the increased benzene groups and the–CF3 groups in the structure, which resulted from the incorporation of the new chain extender, BAPF6P.FPUE had better heat resistance and mechanical properties compared with the conventional PUE.2. Preparation of sulphone-containing polyurethane elastomers (SPUEs) chain-extended by BAPSSPUEs were prepared with TDI-100, PTMG and the chain extender, BAPS. SPUEs were prepared in a two-step method, which was the same with preparation of FPUEs. PUE with the conventional chain-extender MOCA was prepared to be compared with the new elastomer.The morphologies and properties of SPUEs were analyzed with the measurements of FTIR, WAXD, AFM, TGA, DMA and tensile tests. The results showed that the degree of microphase separation was high, and the heat resistance and mechanical properties were excellent because of the increased benzene groups and sulphone groups in the structure, which resulted from the incorporation the new chain extender, BAPS. SPUE had better heat resistance and mechanical properties compared with the conventional PUE.