Bandyopadhyay Jayita, Maity Arjun, Khatua Bhanu Bhusan, Ray Suprakas Sinha
DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria 0001, Republic of South Africa.
J Nanosci Nanotechnol. 2010 Jul;10(7):4184-95. doi: 10.1166/jnn.2010.2991.
The thermal and rheological properties of clay-containing poly[(butylene succinate)-co-adipate] (PBSA) nanocomposites are reported. The nanocomposites of PBSA with various weight percentages of organically modified montmorillonite (OMMT) loadings have been prepared by melt-mixing in a batch-mixer. The melting and crystallization behaviours of PBSA and its nanocomposites have been studied using differential scanning calorimeter (DSC). The melt-state rheological properties of pure PBSA and its nanocomposites containing different amounts of OMMT have been studied in detail. The reason for this is that the rheological responses of any nanofilled polymeric materials are strongly related by their dispersed structure and the interfacial characteristic. Results show that the structural strength of all samples remains constant in the examined time interval at an experimental temperature. The dominant viscous behaviour of pure PBSA is getting suppressed up to a certain OMMT loading (4 wt%). Nanocomposite containing 5 wt% OMMT is showing almost "at the gel point" behaviour, suggesting that the material is behaving near the borderline between liquid and solid; while nanocomposite containing 6 wt% OMMT is showing the gel character. The dispersed structure of the clay particles in the PBSA matrix was studied by scanning transmission electron microscopy (STEM). Results show that the stacked and intercalated silicate layers are nicely dispersed in the case of all nanocomposites. However, with a systematic increase in OMMT loading, the dispersed clay structure of the nanocomposites changes from a highly delaminated to a flocculated and then to a stacked-intercalated structure. In the case of all nanocomposites, melt-state rheological properties are in good agreement with the STEM observations.
本文报道了含粘土的聚（丁二酸丁二醇酯 - 共 - 己二酸酯）（PBSA）纳米复合材料的热性能和流变性能。通过在间歇式混合器中熔融共混制备了具有不同重量百分比有机改性蒙脱土（OMMT）负载量的PBSA纳米复合材料。使用差示扫描量热仪（DSC）研究了PBSA及其纳米复合材料的熔融和结晶行为。详细研究了纯PBSA及其含有不同量OMMT的纳米复合材料的熔体状态流变性能。其原因在于任何纳米填充聚合物材料的流变响应都与其分散结构和界面特性密切相关。结果表明，在实验温度下，所有样品的结构强度在检查的时间间隔内保持恒定。纯PBSA的主要粘性行为在一定的OMMT负载量（4 wt％）之前受到抑制。含有5 wt％OMMT的纳米复合材料表现出几乎“处于凝胶点”的行为，这表明该材料的行为接近液体和固体之间的边界；而含有6 wt％OMMT的纳米复合材料表现出凝胶特性。通过扫描透射电子显微镜（STEM）研究了粘土颗粒在PBSA基体中的分散结构。结果表明，在所有纳米复合材料的情况下，堆叠和插层的硅酸盐层都很好地分散。然而，随着OMMT负载量的系统增加，纳米复合材料的分散粘土结构从高度分层变为絮凝，然后变为堆叠插层结构。在所有纳米复合材料的情况下，熔体状态流变性能与STEM观察结果良好吻合。
