Evolution of phase morphology and ‘network‐like’ structure of multiwall carbon nanotubes in binary polymer blends during melt‐mixing

Polyamide6 (PA6)/acrylonitrile butadiene styrene copolymer (ABS) blends with unmodified multiwall carbon nanotubes (MWNTs) were prepared via melt‐blending in a conical twin‐screw micro‐compounder with varying melt‐mixing time. To improve the state of dispersion of MWNTs, non‐covalent organic modifiers for MWNTs have been utilized: sodium salt of 6‐amino hexanoic acid (Na‐AHA) and 1‐pyrene‐carboxaldehyde (PyCHO). PA6/ABS blends with MWNTs have shown a phase morphology transition from ‘matrix‐dispersed droplet’ type to ‘co‐continuous’ type as a function of melt‐mixing time with the exception of 40/60 PA6/ABS blend with PyCHO‐modified MWNTs. Non‐isothermal crystallization studies revealed the heterogeneous nucleating action of MWNTs through the presence of double crystallization exothermic peaks (at ∼192 ° C and >200 ° C) while pure PA6 shows bulk crystallization peak at ∼192°C. 40/60 and 60/40 (wt/wt) PA6/ABS blends with 5 wt% unmodified MWNTs exhibited electrical conductivity values of ∼3.9 × 10 −11 S/cm and ∼4.36 × 10 −6 S/cm, respectively. A significant enhancement in electrical conductivity was observed with Na‐AHA and PyCHO‐modified MWNTs (order of ∼10 −6 and ∼10 −4 S/cm, respectively). POLYM. ENG. SCI., 55:429–442, 2015. © 2014 Society of Plastics Engineers