Effect of Carbon Particles with Different Topological Shape on the Rheological Behavior of PVA Aqueous Dispersion
Effect of Carbon Particles with Different Topological Shape on the Rheological Behavior of PVA Aqueous Dispersion
复制标题
不同拓扑形状碳颗粒对PVA水分散体流变行为的影响
DOI：
10.1007/s10118-022-2777-2
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发表时间：
2022-07-20
影响因子：
4.3
通讯作者：
Zheng, Qiang
中科院分区：
文献类型：
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作者：
Ni, Qing-Sheng;Du, Miao;Zheng, Qiang
聚乙烯醇（PVA）通常以水分散体的形式加工和使用。大量的分子间和分子内氢键使其很难获得适合加工的流变行为。在本研究中，将不同拓扑形状的碳颗粒加入到聚乙烯醇水分散体系中，以调节聚乙烯醇水分散体系的稳态和动态流变行为。结果表明，零维粒子（炭黑，CB）单调增加PVA分散体的零剪切粘度，一维粒子（碳纳米管，CNTs）使其先增加后降低再上升，呈n型，二维粒子（氧化石墨烯，GO）使其先降低后增加，呈u型。人们认为这些差异是由碳粒子的拓扑形状造成的。零维粒子由于体积小，主要作为物理交联点。而在一定含量下，CNTs和GO都可以破坏PVA链之间的分子间氢键，因为PVA链可以缠绕在细长的CNTs上，而GO的大平面尺寸阻止了吸附的PVA与其他链形成氢键。碳颗粒表面的高羟基值会加强这种效果。期望在制备复合功能材料时，聚合物分散体的粘度可以通过具有不同拓扑形状和表面特性的颗粒来调节，从而扩大可操作的浓度范围。
Poly(vinyl alcohol) (PVA) is usually processed and used in a form of aqueous dispersion. A large number of inter- and intramolecular hydrogen bonds make it very difficult to obtain suitable rheological behavior for processing. In this study, carbon particles with different topological shapes were added into PVA aqueous dispersion to tune the steady and dynamic rheological behavior. The results show that the zero-dimensional particles (carbon black, CB) increase monotonically the zero-shear viscosity of PVA dispersion, while the one-dimensional particles (carbon nanotubes, CNTs) make it first increase, and then decrease and rise again, like an N-shape, and the two-dimensional particles (graphene oxide, GO) can make it first decrease and then increase, exhibiting a U-shape. It is believed that the topological shape of the carbon particles brought about these discrepancies. The zero-dimensional particles mainly act as physical crosslinking points due to their small size. While at a certain content, both CNTs and GO can destroy the intermolecular hydrogen bonds between PVA chains because the PVA chains can twine around the slim CNTs and the large planar size of GO prevents the adsorbed PVA from forming hydrogen bond with other chains. The high hydroxyl value of carbon particle surface could strengthen this effect. It is expected that the viscosity of polymer dispersion can be regulated by particles with different topological shape and the surface characteristic, so as to widen the operable concentration range during preparing composite functional materials.