Elaboration of poly(lactic acid)/halloysite nanocomposites by means of water assisted extrusion: structure, mechanical properties and fire performance
Elaboration of poly(lactic acid)/halloysite nanocomposites by means of water assisted extrusion: structure, mechanical properties and fire performance
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DOI：
10.1039/c4ra06845a
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发表时间：
2014-11
期刊：
影响因子：
3.9
通讯作者：
G. Stoclet;M. Sclavons;B. Lecouvet;J. Devaux;P. V. Velthem;A. Boborodea;S. Bourbigot;N. Sallem-Idrissi
中科院分区：
文献类型：
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作者：
G. Stoclet;M. Sclavons;B. Lecouvet;J. Devaux;P. V. Velthem;A. Boborodea;S. Bourbigot;N. Sallem-Idrissi
采用水辅助挤出工艺制备聚乳酸（PLA）/埃洛石纳米管（HNT）纳米复合材料。将这些纳米复合材料的形态、结构、热机械性能和阻燃性能与通过传统挤出工艺获得的纳米复合材料进行比较。无论采用何种合成路线，机械测试表明 HNT 具有增强效果，至少部分归因于 HNT 在 PLA 基质中的分散。差示扫描量热法还表明，HNT 可以改善 PLA 结晶并发挥成核剂的作用。此外，锥形量热仪实验表明，添加 HNT 后，PLA 的防火反应性显着改善，尤其是在高填料含量的情况下。这种改进源于 HNT 诱导在样品表面形成保护性无机层的事实。这项研究的主要结果表明，水辅助挤出不仅使 HNT 更好地分散到基质中，而且该过程还可以防止挤出过程中聚合物的降解。这种不寻常的效应归因于优先位于 HNT-基质界面的水分子的屏障效应。即使没有完全解释，也可能归因于局部剪切水平的降低（机械化学效应）和/或 HNT 表面催化效应的降低（化学效应）。因此，这项研究表明，水辅助挤出是制备具有增强性能的 PLA/埃洛石纳米复合材料的可靠途径。
Poly(lactic acid) (PLA)/halloysite nanotube (HNT) nanocomposites were prepared using a water assisted extrusion process. Morphology, structure, thermomechanical properties and flame retardant properties of these nanocomposites were compared to those obtained in the case of nanocomposites obtained via the conventional extrusion process. Whatever the synthesis route used, mechanical tests indicate that HNTs have a reinforcing effect ascribed, at least partially, to the dispersion of the HNTs in the PLA matrix. Differential scanning calorimetry also shows that HNTs improve PLA crystallization and play the role of a nucleating agent. Moreover, cone calorimeter experiments show a drastic improvement in the reaction to fire of PLA when HNTs are added, especially at high filler content. This improvement arises from the fact that HNTs induce the formation of a protective inorganic layer at the surface of the sample. As the main results of this study, it has been shown that water assisted extrusion not only induced a better dispersion of the HNTs into the matrix but also that this process prevents polymer degradation during the extrusion. This unusual effect has been ascribed to a barrier effect of the water molecules that preferentially locate at the HNT–matrix interface. Even if not fully explained, it could be ascribed to a decrease in local shear levels (mechanochemical effect) and/or to a decrease in the catalytic effect of the HNT surface (chemical effect). Consequently this study reveals that water-assisted extrusion is a reliable route to prepare PLA/halloysite nanocomposites with enhanced properties.