Mechanics of polymer-clay nanocomposites
Mechanics of polymer-clay nanocomposites
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DOI：
10.1021/ma061445w
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发表时间：
2007-01-23
期刊：
影响因子：
5.5
通讯作者：
Pochan, John M.
中科院分区：
文献类型：
--
作者：
Rao, YuanQiao;Pochan, John M.
纳米复合材料的力学对于设计具有理想性能的纳米材料至关重要。本文采用设计的聚合物和溶液纳米复合材料合成方法，研究了聚合物-粘土纳米复合材料的力学性能。合成了一种具有与粘土纳米片表面强烈相互作用的官能团且玻璃化转变温度低于室温的共聚物乳液。均匀分散的纳米复合材料，然后使用水作为插层剂，通过溶液过程中产生。动态力学热分析（DMTA）和介电热分析（DETA）研究表明，纳米复合材料中的链流动性大大降低。复合材料的模量显著增加。模量增强强烈地与所添加的粘土的体积以及受约束的聚合物的体积相关。这种模量的提高遵循幂律与粘土的含量，并模拟了这种软聚合物基纳米复合材料的门尼方程。建模表明，当基质相的模量远低于粘土的模量时，即，E-f/E-m > 100。本研究还表明，具有强界面相互作用的粘土纳米复合材料的结构类似于半结晶聚合物。在聚合物-粘土纳米复合材料的情况下，插层粘土相作为不可熔的结晶相，导致机械和热性能的改善。
The mechanics of nanocomposites is critical in the design of nanomaterials with desirable properties. In this paper, the mechanics of polymer-clay nanocomposites is studied using a designed polymer and solution nanocomposite synthesis. A copolymer latex, with function groups that strongly interact with the surface of the clay nanoplatelet and glass-transition temperature lower than room temperature, was synthesized. Uniformly dispersed nanocomposites were then generated using water as the intercalation agent through the solution process. The chain mobility in the nanocomposites is greatly reduced as studied by dynamic mechanical thermal analysis (DMTA) and dielectric thermal analysis (DETA). The modulus of the composite increases significantly. The modulus enhancement strongly relates to the volume of the added clay as well as the volume of the constrained polymer. This modulus enhancement follows a power law with the content of the clay and is modeled well by Mooney's equation for this soft-polymer-based nanocomposite. Modeling suggests that the nanocomposite modulus enhancement is determined by the high aspect ratio of the intercalated clay and the strong interfacial strength, in the form of the Einstein coefficient, K, when the modulus of the matrix phase is much lower than that of the clay, i.e., E-f/E-m > 100. This study also indicates that the structure of clay nanocomposites with strong interfacial interactions is analogous to that of semicrystalline polymers. In the case of polymer-clay nanocomposites, the intercalated clay phase serves as an unmeltable crystalline phase that results in improvement in mechanical and thermal properties.