Qualifying Dispersion and Distribution of Carbon Nanotubes in Polyamide Matrix during Melt-Mixing by Flow Simulation

Abstract

This work aims at numerically simulating the flow of nanocomposites in a twin-screw mixer so as to develop a prediction tool of nanofiller dispersion and distribution in a polymer matrix during processing. The rheological behaviour of polyamide 6 / carbon nanotubes blends (PA6/MWCNT) containing from 1 to 5 wt.% of MWCNT was investigated over a large range of shear rates (0.1 to 100 s−1) and temperatures (230 to 245 °C). The macroscopic dispersion of the nanotubes was assessed by dynamic rheometry. Viscosity laws of the nanocomposites were characterized and implemented in a finite element software package to compute the velocity, pressure and temperature fields during the mixing process. A good agreement was founded between the calculated and measured torques. The dispersive and distributive capability of the flow was numerically evaluated and compared to the nanotubes dispersion quality experimentally qualified by oscillatory rheometry. Experimental and numerical results are complementary and allow better understanding the mixing capability of the twin-screw mixer used to compound nanocomposites.

Agglomerated carbon nanotubes effects on buckling behavior of fiber metal laminated nanocomposite shells

“…14 Tuo et al 15 investigated the dispersion states of carbon black (CB) and carbon nanotube (CNT)-reinforced composites. Also, the dispersion and distribution of CNTs in polymer matrix during manufacturing procedure of nanocomposites were investigated by Loux et al 16 Shi et al 17 presented a micromechanical model for studying the effect of CNTs agglomeration on the effective elastic modulus of CNTR composites. It is assumed that a large amount of CNTs are concentrated in some local regions of the matrix and the volume fraction of CNTs is much more than the average volume fraction of CNTs.…”

Melt shear flow behavior of flame-retardant polypropylene composites filled with microencapsulated red phosphorus

“…Therefore, torque rheometry is usually used in polymer processing for characterizing the processing properties of polymeric materials. 8 –10 In 2009, Freire et al 11 studied the processability of poly(vinylidene fluoride)/poly(methyl methacrylate) blends using a torque rheometry and found that the increase in the poly(methyl methacrylate) content improved the processability of the blends, in spite of an increase in the activation energy of flow.…”