Aggregates of Chemically Functionalized Multiwalled Carbon Nanotubes as Viscosity Reducers.
Aggregates of Chemically Functionalized Multiwalled Carbon Nanotubes as Viscosity Reducers.
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DOI：
10.3390/ma7043251
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发表时间：
2014-04-22
期刊：
影响因子：
--
通讯作者：
Giordano M
中科院分区：
文献类型：
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作者：
Petriccione A;Zarrelli M;Antonucci V;Giordano M
纳米颗粒提供的限制和表面效应已被证明会引起聚合物分子的变化，影响其宏观粘度。纳米粒子可能会引起聚合物构象的重排，自由体积的增加会显着降低粘度。这种现象通常归因于当聚合物的旋转半径与纳米颗粒的特征尺寸相当时，高摩尔质量分数的聚合物选择性地吸附在纳米颗粒表面。碳纳米管具有较高的比表面积和纳米尺寸，可与高分子链的回转半径相媲美，是诱导聚合物降粘的理想候选材料。然而，聚合物体系中纳米管的数量受到渗流阈值的限制，因为超过这个限制，纳米管网络的形成会阻碍降粘效果。基于这些发现，我们使用多壁碳纳米管“聚集体”作为降粘剂。我们的结果表明，纳米管团簇的使用显著降低了最终体系的粘度，并显著提高了粘度阻碍的纳米管极限浓度。通过使用羟基和羧基功能化的纳米管，由于纳米管聚集体的氢桥连稳定，这种效果可能得到了相当大的提高。
Confinement and surface effects provided by nanoparticles have been shown to produce changes in polymer molecules affecting their macroscopic viscosity. Nanoparticles may induce rearrangements in polymer conformation with an increase in free volume significantly lowering the viscosity. This phenomenon is generally attributed to the selective adsorption of the polymer high molar mass fraction onto nanoparticles surface when the polymer radius of gyration is comparable to the nanoparticles characteristic dimensions. Carbon nanotubes seem to be the ideal candidate to induce viscosity reduction of polymer due to both their high surface-to-volume ratio and their nanometric sizes, comparable to the gyration radius of polymer chains. However, the amount of nanotube in a polymer system is limited by the percolation threshold as, above this limit, the formation of a nanotubes network hinders the viscosity reduction effect. Based on these findings, we have used multiwalled carbon nanotubes MWCNT “aggregates” as viscosity reducers. Our results reveal both that the use of nanotube clusters reduce significantly the viscosity of the final system and strongly increase the nanotube limiting concentration for viscosity hindering. By using hydroxyl and carboxyl functionalized nanotubes, this effect has been rather maximized likely due to the hydrogen bridged stabilization of nanotube aggregates.