Development of Filler Structure in Colloidal Silica-Polymer Nanocomposites
Development of Filler Structure in Colloidal Silica-Polymer Nanocomposites
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DOI：
10.1021/ma201714u
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发表时间：
2011-10-25
期刊：
影响因子：
5.5
通讯作者：
Weigand, Steven
中科院分区：
文献类型：
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作者：
Meth, Jeffrey S.;Zane, Stephen G.;Weigand, Steven
聚合物纳米复合材料的性能改进的全部潜力的实现依赖于某些性能的最大颗粒-基质界面面积的能力。利用二氧化硅在非水溶剂中作为布朗斯特碱的电荷稳定特性，可以在聚苯乙烯和聚甲基丙烯酸甲酯基质中制备分散良好的纳米复合材料。我们证明了二甲甲酰胺中胶体二氧化硅的分散体是电荷稳定的，而不考虑有机硅的表面功能化。当与聚合物溶液配制时，在干燥过程中保持电荷稳定结构，直到带电双层坍塌。虽然颗粒在中和后可以自由扩散和聚集，但增加的基质粘度延缓了动力学。我们展示了高分子量聚合物如何帮助固定二氧化硅的结构，以产生分散良好的复合材料。这些复合材料的玻璃化转变温度不会变化，即使负载高达50 vol %。
The realization of the full potential for polymeric nanocomposites to manifest their entitled property improvements relies, for some properties, on the ability to achieve maximum particle-matrix interfacial area. Well-dispersed nanocomposites incorporating colloidal silica as the filler can be realized in both polystyrene and poly(methyl methacrylate) matrices by exploiting the charge stabilized nature of silica in nonaqueous solvents which act as Bronsted bases. We demonstrate that dispersions of colloidal silica in dimethylformamide are charge stabilized, regardless of organosilyl surface functionalization. When formulated with polymer solutions, the charge stabilized structure is maintained during drying until the charged double layer collapses. Although particles are free to diffuse and cluster after this neutralization, increased matrix viscosity retards the kinetics. We demonstrate how high molecular weight polymers assist in immobilizing the structure of the silica to produce well-dispersed composites. The glass transition temperatures of these composites do not vary, even at loadings up to 50 vol %.