PMMA nanocomposites with graphene oxide hybrid nanofillers

Abstract

Polymethylmethacrylate (PMMA) and nanocomposites containing 0.5 wt.% graphene oxide (GO), graphene oxide-multiwalled carbon nanotubes (NT) or graphene oxide-ionic liquid 1-octyl-3-methylimidazolium tetrafluoroborate (IL) (PMMA+GO; PMMA+GO-NT; PMMA+GO-IL) were processed by a single step twin-screw micro-extrusion. The effect of two extrusion temperature profiles and two specific mechanical energy (SME) values has been studied. Results of Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis show changes in GO composition and morphology, and better dispersion due to interaction with IL. Dynamic mechanical analysis shows that extrusion conditions affect storage modulus of hybrid nanocomposites. Rheological measurements show that the complex viscosity of the nanocomposites is higher than that of PMMA at low shear rates for materials processed under the lower value of SME. A maximum viscosity increase of 62.6% is found for PMMA+GO-NT. The lowest increase found for PMMA+GO-IL, is attributed to the better dispersion of the hybrid GO-IL nanofiller.

Extrusion of Polymer Nanocomposites with Graphene and Graphene Derivative Nanofillers: An Overview of Recent Developments

“…In this case, the dispersion of IL-modified graphene resulted in a better dispersion of the nanophase. The obtained nanocomposites showed higher mechanical and electrical properties [78] (see Figure 2) and better processability [21]. Low concentrations of GO are used in PMMA matrices in presence of 1 wt.% TiO 2 processed by using twin-screw extrusion [79] with potential dental applications.…”

“…Although PP and PLA (see below) are the most widely studied matrices for graphene nanocomposites, many other thermoplastic materials have also been modified to obtain graphene nanocomposites (Table 3) [21,.…”

“…Other widely used thermoplastics include polystyrene (PS), thermoplastic polyurethane (TPU) or poly (methylmethacrylate) (PMMA) matrices [21,78,79]. Ionic liquids have been utilized to modify the surface of the nanophase aiming at better dispersibility in the polymeric matrix.…”

“…However, in order to achieve uniform graphene dispersion into highly viscous polymers, it is still necessary to modify the surface of graphene flakes. Although this modification can be made by chemical functionalization, with the formation of new covalent bonds [20], it can be more convenient to use a milder process involving non-covalent surface modification [21]. The ease of preparation of large amounts of graphene oxide, the relatively simple dispersion into polymer matrices and the affinity of GO surface oxygen-containing functional groups towards some macromolecules has made it the nanofiller of choice in many cases.…”

Extruded PLA Nanocomposites Modified by Graphene Oxide and Ionic Liquid

“…The concentration of the additives varied from 1 to 5 wt.% in the case of IL, and 0.5 to 1 wt.% in the case of GO. These ranges were chosen after a bibliographic search and an earlier work [ 22 , 43 , 44 ]. Previous testing showed that the best sample preparation and processability were found when the samples with the concentrations shown in Table 2 were used.…”