原位聚合尼龙6／蒙脱土纳米复合材料的结晶行为

Crystallization Behavior of the Nylon- 6/montmorillonite Nanocomposites Prepared by In--situ Polymerization

本文用原位聚合的方法制备了尼龙6／蒙脱土纳米复合材料，通过高速离心沉降实验和XRD表征了蒙脱土在复合材料中的剥离程度和分散状态；采用解偏振光强度法研究了复舍材料的等温结晶过程，并用偏光显微镜观察了其结晶形态；通过DSC研究了复舍材料的非等温结晶动力学，并用Kissinger法计算了复舍材料的结晶活化能。结果表明，蒙脱土在复合材料中完全剥离，以纳米片层的形式均匀分散在基体尼龙6中，蒙脱土的纳米片层对基体的结晶过程起异相成核作用；在蒙脱土的含量较低时，复合材料的结晶速率明显提高，但当蒙脱土的含量较高时，由于蒙脱土纳米片层对结晶生长的阻碍作用占主导地位，复舍材料的结晶速率有所下降，复合材料的结晶活化能也表现出类似的行为。

In this paper, the nylon--6/montmorillonite nanocomposites were prepared by in--situ polymerization in bulk. The dispersion of montmorillonite （MMT） in the composites was explored by high speed ultra--centrifugation and X--ray diffraction （XRD）, and it was shown that the nano--layers of montmorillonite were exfoliated, completely and dispersed homogenously in the matrix for all composites. The isothermal and non--isothermal crystallization kinetics of the composites and pure nylon--6 were studied by the depolarized light intensity （DLI） method and differential scanning caloriometry （DSC） respectively, besides, the morphology of the crystals of the nylon--6 in the isothermal crystallization process was observed by the polarized optical microscopy. It was found that the nano--layers of the montmorillonite acted as nucleators in the crystallization process of nylon--6, and accelerated the crystallization rate of nylon--6. However, when the content of montmorillonite reached 4 phr, the obstacle of the montmorillonite nano--layers to the growth of the crystallites predominated over the nucleation, and the crystallization rate of the composites was decreased somewhat; the activation energy for crystallization of nylon-- 6 and its composites with MMT exhibited similar behavior.