Specific interactions and reactive coupling induced dispersion of multiwall carbon nanotubes in co continuous polyamide6/ionomer blends

An efficient strategy to achieve electrical conductivity in melt-mixed co-continuous blends is to restrict the conducting filler in a particular phase in the blends next to forming a percolated 'network-like' structure in that particular phase. However, strong inter-tube van der Waals' forces often lead to the aggregated structure leading to higher percolation threshold. In addition, the migration of the conducting filler during melt-mixing and the blending sequence significantly affect the bulk conductivity of the blends. SEM observation showed fine co-continuous structures associated with 50/50 blends of PA6/Surlyn with multiwall carbon nanotubes (MWNT). MWNT were localized in the vicinity of the ionic domains in the ionomer corresponding to a specific blending sequence when unmodified MWNT were used, however, in presence of Na-salt of 6-amino hexanoic acid (Na-AHA) modified MWNT, selective clustering was not observed may be due to the confinement of MWNT in the PA6 phase. To understand these complexities the electrical conductivity of melt-mixed blends of polyamide6/ionomer with MWNT was studied. However, it was observed that the blends with even 3 wt% unmodified MWNT showed insulating behaviour irrespective of the blending sequence adopted. in addition, the key role of a reactive modifier (Na-AHA) in facilitating uniform dispersion and subsequent 'network-like' formation by establishing specific interactions with MWNT was studied. it was found that the MWNT are selectively localized in the PA6 phase in the NA-AHA modified blends manifesting in higher electrical conductivity (similar to 10(-5) S/cm at 3 wt% MWNT) when using a specific blending sequence, due to melt-interfacial reaction between the similar to NH2 functionality of Na-AHA and the similar to COOH end groups of PA6. FTIR and Raman spectroscopic analysis also supported the existence of the specific interactions.