Effect of Introduction of Terminal Functions on Properties of Multi-walled Carbon Nanotube/Polystyrene-block-poly(ethylene-co-butylene)- block-polystyrene Composites

摘要

The effects of interfacial adhesion between multi-walled carbon nanotubes (MWCNTs) and terminal-functionalized polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS) matrices have been investigated by determining the mechanical properties of these composites. SEBS with no functionalization (SEBS-1) and SEBSs functionalized by carboxylic acid group (SEBS-3), amino group (SEBS-4), and maleic acid anhydride groups on the middle block (SEBS-2) were used. The nanocomposites were prepared by using a roll mill. The tensile properties and electric conductivity of all the composites improved with increasing MWCNT content. In the SEBS-4 composite system, the tensile moduli were almost three times higher than those of pure SEBS-4 with 17.8 vol% of MWCNT. Further, the electric percolation threshold of CNT/SEBS-4 was higher than that of the others; this indicates that the terminal amino group significantly contributes to the interfacial adhesion, even when the content of the terminals is relatively low. In mechanical analysis of the composites, a broad loss tangent peak appeared at the temperature region between the glass transition point of the mid-block and the polystyrene block. These results suggest that a stereoscopic network structure is formed by the loading of MWCNTs.