Graphene oxide/waterborne polyurethane nanocoatings: effects of graphene oxide content on performance properties
Graphene oxide/waterborne polyurethane nanocoatings: effects of graphene oxide content on performance properties
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DOI：
10.1007/s11998-019-00267-6
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发表时间：
2020-01-01
影响因子：
2.3
通讯作者：
Nguyen, T.
中科院分区：
文献类型：
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作者：
Bernard, C.;Goodwin, D. G., Jr.;Nguyen, T.
氧化石墨烯（GO）具有优异的物理和机械性能，在水中具有良好的分散性，并且相对于石墨烯具有较低的成本，是水性涂料中一种很好的纳米填料。在这里，我们报告了一种单组分水性聚氨酯（WPU）纳米涂层的性能，该涂层具有四种不同的氧化石墨烯负载（质量为[0.4%至2.0%]）。使用扫描电子显微镜、激光扫描共聚焦显微镜和拉曼显微镜评估氧化石墨烯的分散/粘附程度。使用动态机械热分析仪评估纳米涂层的机械性能，使用定制的库伦渗透仪评估氧屏障性能，使用燃烧微热计评估可燃性，使用热盘分析仪评估导热性，使用热重分析仪评估热稳定性，使用吸湿分析仪评估吸水性。结果表明，氧化石墨烯薄片在WPU中分散良好，与WPU的附着力较好。在较高的质量负荷（[1.2%或2%]质量）下，氧化石墨烯使WPU的模量和屈服强度分别提高了300%和200%，导热系数提高了38%，燃烧放热率（可燃性）降低了43%，氧渗透率降低了7倍。然而，氧化石墨烯的存在增加了高湿条件下的水蒸气吸收量；在90%相对湿度下，2%质量负载的氧化石墨烯/WPU纳米涂层的水分含量几乎是未填充WPU的两倍。总的来说，除了在非常高的湿度（约70% RH）下吸水，观察到的物理和机械性能的改善以及加工的便利性表明，氧化石墨烯是一种可行的WPU涂层纳米填料。
Graphene oxide (GO) is a good nanofiller candidate for waterborne coatings because of its outstanding physical and mechanical properties, good dispersibility in water, and low cost relative to graphene. Here, we report on the performance of a one-part, waterborne polyurethane (WPU) nanocoating formulated with four different GO loadings ([0.4% to 2.0%] by mass). The degree of GO dispersion/adhesion was evaluated using scanning electron microscopy, laser scanning confocal microscopy, and Raman microscopy. Nanocoating performance was evaluated using a dynamic mechanical thermal analyzer for mechanical properties, a customized coulometric permeation apparatus for oxygen barrier properties, a combustion microcalorimeter for flammability, a hot disk analyzer for thermal conductivity, thermogravimetric analysis for thermal stability, and a moisture sorption analyzer for water uptake. The results show that GO sheets were well dispersed in, and have good adhesion to, WPU. At the higher mass loadings ([1.2% or 2%] by mass), GO increased the modulus and yield strength of WPU by 300% and 200%, respectively, increased the thermal conductivity by 38%, reduced the burning heat release rate (flammability) by 43%, and reduced the oxygen permeability by up to sevenfold. The presence of GO, however, increased water vapor uptake at high humidity; the moisture content of 2% mass loading GO/WPU nanocoatings at 90% RH was almost twice that of the moisture content for unfilled WPU. Overall, with the exception of water uptake at very high humidity (> 70% RH), the observed improvements in physical and mechanical properties combined with the ease of processing suggest that GO is a viable nanofiller for WPU coatings.