Nanostructured polyurethane/POSS hybrid aqueous dispersions prepared by homogeneous solution polymerization
Nanostructured polyurethane/POSS hybrid aqueous dispersions prepared by homogeneous solution polymerization
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DOI：
10.1021/ma060809h
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发表时间：
2006-10-03
期刊：
影响因子：
5.5
通讯作者：
Otaigbe, Joshua U.
中科院分区：
文献类型：
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作者：
Nanda, Ajaya K.;Wicks, Douglas A.;Otaigbe, Joshua U.
用4-10重量%的官能化的多面体低聚倍半硅氧烷（POSS）通过在丙酮中的均相溶液聚合，然后用水进行溶剂交换来制备水性聚氨酯分散体。使用丙酮作为初始聚合溶剂允许在均相反应环境中容易地掺入二氨基和二羟基官能化POSS单体。在加入水和除去丙酮后，获得具有单峰粒径的稳定分散体。POSS单体的掺入对分散体的性质没有显著影响;然而，分离的聚合物的物理性质确实显示出显著变化，储能模量、Tg、复数粘度和表面疏水性显著增加。这些变化归因于POSS残基掺入到聚氨酯硬段域中发现，虽然没有任何迹象的任何毛相异质性，由于包括POSS部分检测到的热表征或广角X-射线衍射（WAXD），原子力显微镜（AFM）观察到一个显着的变化时，样品从有机溶剂中重铸。
Aqueous polyurethane dispersions were prepared with 4-10 wt% of functionalized polyhedral oligomeric silsesquioxanes (POSS) via homogeneous solution polymerization in acetone followed by solvent exchange with water. The use of acetone as the initial polymerization solvent allowed for the facile incorporation of both diamino and dihydroxy functional POSS monomers in a homogeneous reaction environment. After addition of water and removal of the acetone, stable dispersions with unimodal particle sizes were obtained. The incorporation of the POSS monomers did not have a significant effect on the dispersion's properties; however, the physical properties of the isolated polymers did display significant changes, with notable increases in storage modulus, T-g, complex viscosity, and surface hydrophobicity. These changes were attributed to the incorporation of the POSS residues into the polyurethane hard segment domains found. Though no sign of any gross phase heterogeneity due to the inclusion of POSS moieties was detected by either thermal characterization or wide-angle X-ray diffraction (WAXD), a significant change was observed by atomic force microscopy (AFM) when the samples were recast from organic solvent.