Department of Materials Science Engineering, University of Ioannina, 45110 Ioannina, Greece.
J Phys Chem B. 2013 Jan 24;117(3):907-15. doi: 10.1021/jp309361b. Epub 2013 Jan 10.
Polystyrene-b-polyisoprene-b-polystyrene (PS-b-PI-b-PS), a widely used linear triblock copolymer of the glassy-rubbery-glassy type, was prepared in this study by anionic polymerization and was further used for the development of novel polymer nanocomposite materials. Hybrid nanoadditives were prepared by the catalytic chemical vapor deposition (CCVD) method through which carbon nanotubes were grown on the surface of smectite clay nanolayers. Side-wall chemical organo-functionalization of the nanotubes was performed in order to enhance the chemical compatibilization of the clay-CNT hybrid nanoadditives with the hydrophobic triblock copolymer. The hybrid clay-CNT nanoadditives were incorporated in the copolymer matrix by a simple solution-precipitation method at two nanoadditive to polymer loadings (one low, i.e., 1 wt %, and one high, i.e., 5 wt %). The resulting nanocomposites were characterized by a combination of techniques and compared with more classical nanocomposites prepared using organo-modified clays as nanoadditives. FT-IR and Raman spectroscopies verified the presence of the hybrid nanoadditives in the final nanocomposites, while X-ray diffraction and transmission electron microscopy proved the formation of fully exfoliated structures. Viscometry measurements were further used to show the successful incorporation and homogeneous dispersion of the hybrid nanoadditives in the polymer mass. The so prepared nanocomposites exhibited enhanced mechanical properties compared to the pristine polymer and the nanocomposites prepared by conventional organo-clays. Both tensile stress and strain at break were improved probably due to better interfacial adhesion of the clay-CNT hybrid of the flexible rubbery PI middle blocks of the triblock copolymer matrix.
聚苯乙烯-b-聚异戊二烯-b-聚苯乙烯（PS-b-PI-b-PS）是一种广泛使用的玻璃态-橡胶态-玻璃态线性三嵌段共聚物，本研究通过阴离子聚合制备，并进一步用于开发新型聚合物纳米复合材料。通过催化化学气相沉积（CCVD）方法制备了杂化纳米添加剂，通过该方法在蒙脱石纳米层的表面上生长碳纳米管。对纳米管进行了侧链化学有机官能化，以增强粘土-CNT 杂化纳米添加剂与疏水性三嵌段共聚物的化学相容性。通过简单的溶液沉淀法将杂化粘土-CNT 纳米添加剂掺入共聚物基质中，纳米添加剂与聚合物的负载比为两种（低负载，即 1wt%，高负载，即 5wt%）。通过多种技术对所得纳米复合材料进行了表征，并与使用有机改性粘土作为纳米添加剂制备的更经典的纳米复合材料进行了比较。FT-IR 和拉曼光谱证实了最终纳米复合材料中存在杂化纳米添加剂，而 X 射线衍射和透射电子显微镜证明了完全剥离结构的形成。粘度测量进一步用于表明杂化纳米添加剂在聚合物质量中的成功掺入和均匀分散。与原始聚合物和用传统有机粘土制备的纳米复合材料相比，所制备的纳米复合材料表现出增强的机械性能。断裂拉伸应力和应变都得到了提高，这可能是由于粘土-CNT 杂化增强了柔性橡胶状 PI 中间块与三嵌段共聚物基质之间的界面粘附力。
