Influence of the Filler Nature on the Crystalline Structure of Polylactide-Based Nanocomposites: New Insights into the Nucleating Effect
Influence of the Filler Nature on the Crystalline Structure of Polylactide-Based Nanocomposites: New Insights into the Nucleating Effect
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DOI：
10.1021/acs.macromol.5b02746
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发表时间：
2016-04-12
期刊：
影响因子：
5.5
通讯作者：
Gloaguen, Vincent
中科院分区：
文献类型：
--
作者：
Ouchiar, Saadia;Stoclet, Gregory;Gloaguen, Vincent
这项工作研究了填料性质对聚丙交酯 (PLA) 基纳米复合材料热致晶体结构的影响。特别是两种具有片状形状的硅酸盐粘土，即滑石和高岭土，与PLA熔融复合，并通过广角和小角X射线散射技术原位跟踪等温结晶过程中涉及的晶体结构。结果表明，即使两种类型的粘土在化学性质上相似，即它们都具有硅酸盐表面，但只有滑石粉在 PLA 结晶中起到成核剂的作用。此外，结构分析表明，对于填充滑石粉的PLA纳米复合材料，会发生转晶过程，除了PLA晶体向粘土表面垂直生长外，还可以根据结晶温度形成有序的纳米级结构。特别是，首次证明了外延生长过程，并确定了PLA晶体和滑石片之间的晶体取向关系。相反，高岭土基纳米复合材料没有遇到相同的行为。从基本角度来看，这项研究表明聚合物和填料之间存在有利的相互作用并不是涉及成核效应过程的唯一参数。事实上，填料和聚合物晶体结构之间晶体学关系的存在也是观察成核效应的必要条件。最后，这项工作还强调，将精心选择的填料掺入聚合物基质中可以是诱导纳米结构材料的有效途径。
This work deals with the influence of the nature of a filler on the thermally induced crystalline structure of polylactide (PLA)-based nanocomposites. Particularly two types of silicated clay both having a platelet-like shape, i.e., talc and kaolin, were melt compounded with PLA, and the crystalline structure involved during isothermal crystallization was followed in situ by means of both wide- and small-angle X-ray scattering techniques. Results indicate that even if the two types of clay are chemically similar, i.e., they both exhibit silicate surfaces, only talc plays the role of nucleating agent on the PLA crystallization. Moreover, structural analyses reveal that for PLA nanocomposites filled with talc a transcrystallization process occurs and that, in addition to the perpendicular growth of the PLA crystals toward the clay surface, a well-ordered nanometer scaled structure can be formed depending on the crystallization temperature. Particularly, for the first time, an epitaxial growth process has been evidenced, and crystallographic orientation relationships between the PLA crystals and the talc platelets have been determined. In opposition, the same behavior was not encountered for the kaolin-based nanocomposites. From a fundamental point of view, this study shows that the existence of favorable interactions between the polymer and the filler is not the only parameter involving the nucleating effect process. Indeed, the existence of crystallographic relationships between the filler and the polymer crystalline structure is also a necessary condition to observe a nucleating effect. Finally, this work also highlights that incorporating a well-chosen filler into a polymer matrix can be an efficient route to induce nanostructured materials.