Dynamic mechanical properties of multiwall carbon nanotube reinforced ABS composites and their correlation with entanglement density, adhesion, reinforcement and C factor

Abstract

The dynamic mechanical properties of multiwalled carbon nanotube (MWCNTs) reinforced acrylonitrile butadiene styrene (ABS) high performance composites, which were prepared using a micro twin screw extruder with a back flow channel that enabled proper dispersion of MWCNTs into the polymer matrix are studied in detail. The dynamic characteristics of the MWCNTs/ABS composites, such as storage, loss modulus and damping factor were significantly affected by the incorporation of MWCNTs. The dynamic mechanical properties of polymers strongly depend on the adhesion of MWCNTs and polymer and entanglement density of the polymer chains in the presence of MWCNTs. Herein, the entanglement density and C-factor of MWCNTs/ABS composites are evaluated using the dynamic mechanical properties results obtained from a dynamic mechanical analyser and correlated with their mechanical properties. The entanglement density of the MWCNTs/ABS composites increased from 4.31 × 10⁴ mol m⁻³ (pure ABS) to 7.6 × 10⁴ mol m⁻³ (5 wt% MWCNTs/ABS composites). C-factor measures the effectiveness of the filler on the modulus of the composites, which decreased from 1.086 (1 wt% MWCNTs/ABS composites) to 0.78 (5 wt% MWCNTs/ABS composites), and beyond this loading, the value of C-factor began to increase; this showed that the utilization of 5 wt% MWCNTs in the ABS matrix is sufficient for their effective use. The “b” factor increased from 6.16 (1 wt% MWCNTs/ABS composites) to 7.625 (5 wt% MWCNT/ABS composites) and after that started to decrease. A larger value of “b” strengthens the MWCNTs/ABS matrix interaction. In addition, Cole–Cole analysis was carried out to understand the phase behaviour of the composites.