Luo Yanlong, Chen Xianling, Wu Sizhu, Cao Songyuan, Luo Zhenyang, Shi Yijun
College of Science, Nanjing Forestry University, Nanjing 210037, P. R. China.
Institute of Polymer Materials, Nanjing Forestry University, Nanjing 210037, P. R. China.
Langmuir. 2020 Aug 11;36(31):9291-9305. doi: 10.1021/acs.langmuir.0c01736. Epub 2020 Aug 2.
Solubility parameters play an important role in predicting compatibility between components. The current study on solubility parameters of carbon materials (graphene, carbon nanotubes, and fullerene, etc.) is unsatisfactory and stagnant due to experimental limitations, especially the lack of a quantitative relationship between functional groups and solubility parameters. Fundamental understanding of the high-performance nanocomposites obtained by carbon material modification is scarce. Therefore, in the past, the trial and error method was often used for the modification of carbon materials, and no theory has been formed to guide the experiment. In this work, the effect of defects, size, and the number of walls on the Hildebrand solubility parameter (δ) of carbon nanotubes (CNTs) was investigated by molecular dynamics (MD) simulation. Besides, three-component Hansen solubility parameters (δ, δ, δ) were transformed into two-component solubility parameters (δ, δ). The quantitative relation between functional groups and two-component solubility parameters of single-walled carbon nanotubes (SWCNTs) was then given. An important finding is that the δ and δ of SWCNTs first decrease, reach a minimum, and then increase with increasing grafting ratio. The thermodynamic compatibility between functionalized SWCNTs and six typical polymers was investigated by the Flory-Huggins mixing model. Two-component solubility parameters were proven to be able to effectively predict their compatibility. Importantly, we theoretically gave the optimum grafting ratio at which the compatibility between functionalized SWCNTs and polymers is the best. The functionalization principle of SWCNTs toward good compatibility between SWCNTs and polymers was also given. This study gives a new insight into the solubility parameters of functionalized SWCNTs and provides theoretical guidance for the preparation of high-performance SWCNTs/polymers composites.
溶解度参数在预测组分间的相容性方面起着重要作用。目前关于碳材料（石墨烯、碳纳米管和富勒烯等）溶解度参数的研究由于实验限制并不理想且停滞不前，尤其是缺乏官能团与溶解度参数之间的定量关系。对通过碳材料改性获得的高性能纳米复合材料的基本认识也很匮乏。因此，过去对碳材料的改性常常采用试错法，尚未形成指导实验的理论。在这项工作中，通过分子动力学（MD）模拟研究了缺陷、尺寸和管壁数量对碳纳米管（CNT）的希尔德布兰德溶解度参数（δ）的影响。此外，将三组分汉森溶解度参数（δ、δ、δ）转换为双组分溶解度参数（δ、δ）。随后给出了单壁碳纳米管（SWCNT）官能团与双组分溶解度参数之间的定量关系。一个重要发现是，SWCNT的δ和δ随着接枝率的增加先降低，达到最小值，然后升高。通过弗洛里 - 哈金斯混合模型研究了官能化SWCNT与六种典型聚合物之间的热力学相容性。结果证明双组分溶解度参数能够有效预测它们的相容性。重要的是，我们从理论上给出了官能化SWCNT与聚合物之间相容性最佳时的最佳接枝率。还给出了SWCNT实现与聚合物良好相容性的官能化原理。这项研究为官能化SWCNT的溶解度参数提供了新的见解，并为制备高性能SWCNT/聚合物复合材料提供了理论指导。
