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arXiv 0903.5380cond-mat.mtrl-sci
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在polymer -二氧化硅纳米复合材料中作为填料的良好分散的分形聚集体:流变学的长程效应

Well dispersed fractal aggregates as filler in polymer-silica nanocomposites: long range effects in rheology

Nicolas Jouault, Perrine Vallat, Florent Dalmas, Sylvère Said, Jacques Jestin, François Boué

摘要:

我们提出了一种处理聚苯乙烯-二氧化硅纳米复合材料的新方法,该方法导致小的初级聚集体(15个直径为10 nm的纳米颗粒的组装体)在基质中的非常明确的分散。该方法是基于高沸点溶剂,其中纳米颗粒分散良好,并控制蒸发。填料的精细网络结构是在很宽的尺寸范围内使用小角中子散射(SANS)和透射电子显微镜(TEM)的组合来确定的。纳米复合材料的机械响应进行了研究小(ARES振荡剪切和动态力学分析)和大变形(单轴牵引),作为颗粒浓度的函数。我们可以研究两种主要增强效应的结构-性能相关性:填料网络贡献和填料-聚合物基体效应。在二氧化硅体积分数阈值以上,我们看到与连接网络的建立相关的模量的发散。低于阈值,我们得到一个新的额外的弹性贡献的更长的终端时间比矩阵。由于聚集体分离至少60 nm,这种新的填料-基质贡献不能仅用玻璃态层(2 nm)的概念来描述。

英文摘要:

We are presenting a new method of processing polystyrene-silica nanocomposites, which results in a very well-defined dispersion of small primary aggregates (assembly of 15 nanoparticles of 10 nm diameter) in the matrix. The process is based on a high boiling point solvent, in which the nanoparticles are well dispersed, and controlled evaporation. The filler's fine network structure is determined over a wide range of sizes, using a combination of Small Angle Neutron Scattering (SANS) and Transmission Electronic Microscopy (TEM). The mechanical response of the nanocomposite material is investigated both for small (ARES oscillatory shear and Dynamical Mechanical Analysis) and large deformations (uniaxial traction), as a function of the concentration of the particles. We can investigate the structure-property correlations for the two main reinforcement effects: the filler network contribution, and a filler-polymer matrix effect. Above a silica volume fraction threshold, we see a divergence of the modulus correlated to the build up of a connected network. Below the threshold, we obtain a new additional elastic contribution of much longer terminal time than the matrix. Since aggregates are separated by at least 60 nm, this new filler-matrix contribution cannot be described solely with the concept of glassy layer (2nm).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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