运用动态力学分析(DMA)、原子力显微镜(AFM)和Fourier变换红外光谱(FT-IR)研究了聚天冬氨酸酯(PAE)聚脲的动态力学性质和结构形态的温度依赖性.研究表明,当固化温度由20℃升至80℃时,PAE聚脲的低温和高温储能模量(E')以及硬段玻璃化转变温度(T_(gh))逐渐提高,微相分离程度也逐渐增大;脲羰基的总氢键化程度由74.3%增至82.1%,而NH基氢键键长则由0.307nm减至0.303 nm,硬段结构规整度提高,软段与硬段的相容性降低;借助AMF直观地观察到了PAE聚脲的微相分离结构,并证实了固化温度对微结构的影响.提高固化温度可以改善涂层的微观结构,从而提高涂层的动态力学性质.
The dynamic mechanical properties and morphology of polyaspartic ester (PAE) based ployureas cured at 20℃、40℃ and 80℃ were investigated through dynamic mechanical analysis(DMA), Fourier transform infrared spectroscopic(FT-IR) and atomic force microscope(AFM). Studies indicate that the PAE based polyureas exhibites larger storage modulus (E'), higher glass transition temperature of hard segment (T_(gh)) and microphase separation degree while curing temperature is improved from 20℃ to 80℃. Meanwhile hydrogen-bonded urea carbonyl is improved from 74.3% to 82.1%, the length of hydrogen bonding is reduced from 0.307 nm to 0.303 nm, suggesting that the compatibility of soft and hard segment decreases and microphase separation degree increases with the curing temperature increased. The microphase separation phenomenon of the PAE based polyureas were observed directly through AFM topography studies, and the dependence of microphase separation of PAE based polyureas on curing temperature can be confirmed. Dynamic mechanical properties can be improved while microstructure modified with the curing temperature increased.
参考文献
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