Improving the dispersion of MWCNT and MMT in PVDF melts employing controlled extensional flows

Abstract

Poly (vinylidene fluoride) (PVDF) has been widely explored to produce polymer nanocomposites possessing outstanding combinations of properties. In this work, the impact of extensional melt flows on the dispersion, relaxation and crystallinity of PVDF nanocomposites filled with multiwalled carbon nanotubes (MWCNT) and montmorillonites (MMT) was studied. Extrusion was employed to produce nanocomposites containing 3 wt% of fillers, named: (i) PVDF/3 wt% MWCNT, (ii) PVDF/3wt%MMT, and (iii) PVDF/1.5wt%MWCNT/1.5 wt% MMT. The results showed that applying a sequence of extensional flows through the melts improved the dispersion of both fillers in the PVDF matrix. Moreover, extensional flows significantly enhanced the viscosity and relaxation of MWCNT nanocomposite, but had marginal effects on MMT nanocomposite. On the other hand, MMT favored the crystallization of the β piezoelectric phase of PVDF over the α phase and the extensional flow enhanced its crystallinity content. Therefore, these new insights prospect a vast horizon toward the use of extensional flows for tailoring synergic combinations of properties in hybrid PVDF/MWCNT/MMT systems.

PBAT/PLA/cellulose nanocrystals biocomposites compatibilized with polyethylene grafted maleic anhydride (PE‐g‐MA)

“…In this process, the biocomposite precursors were initially mixed for 5 min and then processed by a mini single screw extruder Filmaq3d STD (Figure 1), operating at 30 rpm screw speed and 170°C, following the previous reports 34 . The biocomposite was extruded through a ring‐shaped matrix, and the obtained filaments were cooled using a water bath system (25°C) and finally collected by a filament winder.…”

“…Schematic illustration of the single‐screw extruder employed, according to Goes et al 34 [Color figure can be viewed at wileyonlinelibrary.com]…”

Effect of the Elongational Flow on the Morphology and Properties of Polymer Systems: A Brief Review

“…A few works reported the effect of the elongational flow in inducing morphology evolution in carbon nanotubes (CNTs)-containing nanocomposites [198][199][200][201][202][203]. Generally, the application of the extensional flow during the processing causes the debundling of the CNT clusters formed during the melt mixing step because of attractive inter-tube interactions, resulting in an improvement of the extent of dispersion of the embedded fillers and in the obtainment of more uniform and homogeneous morphologies.…”

Effect of high aspect ratio flaky aluminum on mechanical properties of epoxy‐based particulate composites

“…[5] In general, it is observed that the rigid additives hinder the movement of polymer molecules leading to an increase in stiffness and strength. [10][11][12][13][14][15] Strength and stiffness also depend on the size, quantity, shape of the additives, and interfacial adhesion. [5] It was observed that beyond a certain volume fraction of the additive, the tensile strength of the composite decreases whereas its elastic modulus increases.…”

“…Metal/polymer composites are attractive alternatives that address these concerns. [14,24,25] However, most of these additives fail to increase the strain at failure or ductility in the material and their strength to weight ratio is less compared to CNTs/nanoclay. [14] Nevertheless, some studies have shown that nanoalumina has been able to marginally increase the ductility in the polymer.…”