Water assisted exfoliation of PA6/clay nanocomposites using a twin screw extruder: Effect of water contact time

Progressing of a power model for electrical conductivity of graphene-based composites

This work presents a power equation for the conductivity of graphene-based polymer composites by the tunneling length, interphase deepness and filler size. The impressions of these factors on the effective concentration and percolation beginning of graphene nano-sheets in nanocomposites are also expressed. The developed equations for percolation beginning and conductivity are examined by the experimented data of some examples, which can guesstimate the interphase depth, tunneling size and percolation exponent. Besides, the impacts of numerous factors on the percolation beginning and conductivity are designed. The developed equation for percolation beginning shows the formation of thick interphase and large tunnels in the reported samples. So, disregarding of tunneling and interphase spaces in polymer graphene nanocomposites overpredicts the percolation beginning. Additionally, the developed model presents the acceptable calculations for the conductivity of samples. Among the mentioned parameters, the concentration and graphene conductivity in addition to the interphase depth induce the strongest effects on the conductivity of composites.

Influence of Processing Conditions on the Preparation of Clay-Based Nanocomposites by Twin-Screw Extrusion

This review paper is devoted to the preparation of clay-based thermoplastic nanocomposites by melt blending in a twin-screw extruder. The influence of the main processing parameters (screw speed, feed rate, barrel temperature, screw profile) on the state of the clay dispersion at the micro- and nanoscale is characterized. The change of dispersion state along the screws and the corresponding mechanisms are presented. The interest of process modelling to predict the state of dispersion is evaluated and, finally, the main modifications of the twin-screw extrusion process to improve the clay dispersion are reviewed.

Water-Assisted Production of Thermoplastic Nanocomposites: A Review

Water-assisted, or more generally liquid-mediated, melt compounding of nanocomposites is basically a combination of solution-assisted and traditional melt mixing methods. It is an emerging technique to overcome several disadvantages of the above two. Water or aqueous liquids with additives, do not work merely as temporary carrier materials of suitable nanofillers. During batchwise and continuous compounding, these liquids are fully or partly evaporated. In the latter case, the residual liquid is working as a plasticizer. This processing technique contributes to a better dispersion of the nanofillers and affects markedly the morphology and properties of the resulting nanocomposites. A survey is given below on the present praxis and possible future developments of water-assisted melt mixing techniques for the production of thermoplastic nanocomposites.