Nanocomposites of Polystyrene-b-Poly(isoprene)-b-Polystyrene Triblock Copolymer with Clay–Carbon Nanotube Hybrid Nanoadditives

Abstract

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.

Thermal and Morphological Study of Epoxy Matrix with Chemical and Physical Hybrid of Nanoclay/Carbon Nanotube

“…It was believed that, in epoxy-0.2 CNC, the exfoliated state of NC in combination with the presence of CNT grown on their surfaces, resulted in the greater improvement of the thermal stability of the composites. 17 It was also noted that the presence of nanofiller was effective in improving the weight residues of the epoxy nanocomposites. The residual mass of the nanocomposites with different type of nanofiller was 1-2 wt.% higher than that of pure epoxy.…”

“…14,15 Recently, the synergistic effect between CNTs and NC in chemical hybrids of them was evidenced with outstandingly enhanced mechanical properties of polymer nanocomposites with respect to the pristine polymer. [16][17][18] Strong interaction between the chemical hybrid and the polymer was proved to be responsible for that significant improvement. 13 Improvement in thermal stability was observed for polyurethane foams, 18 nylon-6 19 and Nafion 20 with chemical hybrids of CNTs and NC.…”

Synthesis, Characterization and Mechanical Properties of Nanocomposites Based on Novel Carbon Nanowires and Polystyrene

“…The mixture was then stirred for 3 h, precipitated with methanol and air-dried on a glass plate. Finally, the solid samples were heated for 2 h under vacuum at 140 • C for the efficient removal of the solvent [21]. The final membrane products were shaped through the compression between two heated platens of Specac's Atlas suitable for Specac's Hydraulic Press.…”

The Meeting Point of Carbonaceous Materials and Clays: Toward a New Generation of Functional Composites

“…More frequently, CNT have been grown by chemical vapor deposition on the surface of the layered clay where a metal catalyst has been previously incorporated. The resulting hybrids could be used as nanofillers of homopolymers, block copolymer and even triblock copolymers, for instance polystyrene‐b‐poly(isoprene)‐b‐polystyrene, for improving mechanical properties. Recently, nanocomposites based on epoxy resins have been characterized in depth, and the improvement of mechanical and thermal properties has been correlated with the organization of the two particles of the nanofiller in 3D structures .…”

“…The recent possibilities to synthetize new forms of carbonaceous materials involving graphene, e.g., carbon nanotubes (CNT) and graphene oxide, as well as the potential to modify clay minerals introducing controlled functionalization using organosilanes or cationic surfactants, offer the opportunity to combine both types of compounds at the nano‐ or the microscale. Such an association translates into an extremely wide range of new hybrid materials provided with novel, complementary, and even synergistic properties . Hence, a novel class of composites prepared by the assembly of the two components represents a challenge aiming at developing improved low‐cost materials provided with predetermined structural and functional behaviors.…”