Good Dispersion Of Graphene Oxide Research Articles

Structure and conformation of polyetheramine in confined space of graphene oxide and its enhancement on the electrically conductive properties of monomer casting nylon-6

Graphene oxide (GO) was functionalized with polyetheramine (PEA) and MC nylon-6/reduced GO (rGO)-PEA composites were in situ synthesized. Intermolecular covalent and hydrogen bonding was confirmed to form for GO/PEA molecules, and the grafting ratio and average layer thickness exhibit a significant increase with PEA loading. Meanwhile the interlayer spacing (d002) of GO-PEA increases steadily, and PEA chains adopt trans and planar zigzag conformation with arrangements of monolayer, bilayer in GO layers in the range of 100–400% PEA, while the completely exfoliated state of GO formed by saturation intercalation of 700% PEA. Compared with GO, the layer stacking of GO-PEA is much more weakened, exhibiting a wrinkled and almost monolayer dispersion state, which leads to a good dispersion of GO (rGO)-PEA in melting caprolactamand a much higher uniformity for the nylon-6 composites. The electrically conductive network formed, resulting in the remarkably improved electrical conductivity of the composites.

Polypropylene nanocomposite with polypropylene-grafted graphene

A method for grafting polypropylene (PP) onto graphene oxide (GO) surfaces was successfully established by functionalizing GO with (3-aminopropyl)triethoxysilane (NH2-t-GO) and grafting maleic-anhydride-grafted PP (MAPP) on NH2-t-GO (MAPP-g-GO). The PP/GO nanocomposites were prepared by compounding MAPP-g-GO with virgin PP. The modulus, tensile strength, and elongation at break of the nanocomposite were improved by 48%, 37%, and 19%, respectively, by incorporating 0.6 wt% MAPP-g-GO (0.06 wt% GO). This improvement in the mechanical properties may be due to the good dispersion of GO in the PP matrix, which can be achieved via the excellent interactions between the grafted PP on GO and the matrix PP.

Maleic anhydride-grafted poly(lactic acid) as a compatibilizer in poly(lactic acid)/graphene oxide nanocomposites

The goal of this work is to study the influence of maleic anhydride-grafted poly(lactic acid) compatibilizer (PLAgMA) on morphology, thermal and barrier properties of poly(lactic acid) (PLA)/graphene oxide (GO) nanocomposites. Graphene oxide was synthesized from graphite flakes using modified Hummers method. The nanocomposites were prepared by the incorporation of graphene oxide into PLA via solution casting. The formation of nanolayers of graphene oxide was confirmed by Fourier transform infrared spectroscopic analysis, scanning electron microscopy and atomic force microscopy measurements. A maximum in elastic modulus G′ measured at low frequencies was identified for the PLA containing 3 wt% GO and 3 wt% PLAgMA, which indicates a better dispersion of GO in the presence of compatibilizer and, therefore, yield better thermal and barrier properties of the nanocomposites.

Physical and mechanical properties of graphene oxide/polyethersulfone nanocomposites

The aim of this study was to investigate physical and mechanical properties of graphene oxide (GO)/polyethersulfone (PES) nanocomposite films. The films were produced by solution casting method. The mechanical properties of composite films were evaluated by tensile test. A significant enhancement in the mechanical properties of neat PES films was obtained incorporating a small amount of GO loading (0.05–1 wt.%). The highest tensile strength was observed at 1 wt.% of GO. Comparisons were made between experimental data and the Halpin–Tsai model predictions for the tensile strength and modulus of GO/PES composites. The effect of an orientation factor on model predictions was also acquired. The hydrophilicity of the nanocomposite was evaluated by assessing contact angle and enhanced wet ability of the films was obtained with increasing the amount of GO up to 1%. The morphology of the nanocomposites was investigated using scanning electron microscopy and transmission electron microscopy and the results revealed a good dispersion of GO in the PES matrix. The thermal behavior of the composite was also studied. Thermal stability of composites was increased by adding the GO. Copyright © 2013 John Wiley & Sons, Ltd.

RGO/Nylon-6 composite mat with unique structural features and electrical properties obtained from electrospinning and hydrothermal process

In this work, the reduced graphene oxide (RGO) sheets were effectively uploaded through nylon-6 fibers using combined process of electrospinning and hydrothermal treatment. Good dispersion of graphene oxide (GO) with nylon-6 solution could allow to upload GO sheets through nylon-6 fibers and facilitate the formation of spider-wave-like nano-nets during electrospinning. GO sheets present on/into nylon-6 spider-wave-like nano-nets were further reduced to RGO using hydrothermal treatment. The impregnated GO sheets into nylon-6 nanofibers and their reduction during hydrothermal treatment were confirmed by FE-SEM, TEM, FT-IR and Raman spectra. The electrical characteristics of pristine nylon-6, GO/nylon-6 and RGO/nylon-6 nanofibers were investigated and it was found that RGO/nylon-6 composite mat had better electrical conductivity than others. The formation of spider-wave-like nano-nets as well as indirect route of incorporation of RGO sheets on electrospun nylon-6 mat may open a new direction for future graphene/polymer electronics.

The curing behavior and thermal property of graphene oxide/benzoxazine nanocomposites

Two series of benzoxazine (BOZ) based composites were prepared with graphene oxide (GO) and graphite via in situ intercalative polymerization. Based on isothermal and non-isothermal mode Differential Scanning Calorimetry results, BOZ with the addition of GO could not only decrease the cure temperature, but also increase the cure rate of BOZ. On the contrary, BOZ with the addition of graphite would delay the polymerization of BOZ monomer. It was hypothesized that carboxyl groups of GO acted as weak organic acid which accelerated the ring opening procedure. Interestingly, BOZ/GO composite with 1 wt% GO occupied the least time to form polymer networks, attributing to the catalytic effect and good dispersion of GO. Moreover, BOZ with 1 wt% content of GO had relatively higher glass transition temperature and char yield than those of the corresponding BOZ/graphite sample, which was due to relatively stronger intermolecular interactions between GO and BOZ.

Synthesis of graphene decorated with silver nanoparticles by simultaneous reduction of graphene oxide and silver ions with glucose

A green and efficient approach for the synthesis of graphene decorated with silver nanoparticles is demonstrated by simultaneously reducing both graphene oxide (GO) sheets and silver ions with glucose as the reducing agent and poly(N-vinyl-2-pyrrolidone) (PVP) as the surface modifier. Different silver-containing materials are obtained by changing the synthesis temperature. The oxygen-containing groups of the substrate influence its decoration with the in situ formed silver nanoparticles. The combination of glucose and a silver–ammonia solution, as well as maintaining a good dispersion of GO by using PVP are crucial for the decoration of graphene with silver nanoparticles. The materials exhibit a distinct surface-enhanced Raman scattering effect.

Poly(ε-caprolactone)/graphene oxide biocomposites: mechanical properties and bioactivity

Biomedical applications of graphene have recently attracted intensive attention, with graphene-based nanomaterials being reported as promising candidates in, for example, drug delivery, biosensing and bioimaging. In this paper, mechanical properties and bioactivity of nanofibrous and porous membranes electrospun from graphene oxide (GO) nanoplatelets reinforced poly(ε-caprolactone) (PCL) were investigated. The results showed that the presence of 0.3 wt% GO increased the tensile strength, modulus and energy at break of the PCL membrane by 95%, 66% and 416%, respectively, while improving its bioactivity during biomineralization and maintaining the high porosity of over 94%. The mechanical enhancements were ascribed to the change in the fiber morphology and the reinforcing effect of GO on PCL nanofibers, whereas the improvements on the bioactivity stemmed from the anionic functional groups present on the GO surface that nucleated the formation of biominerals. Systematic studies on the PCL/GO nanocomposite films with varying GO concentrations revealed that the reinforcing effect of GO on PCL was due to the strong interfacial interactions between the two phases characterized by Fourier transform infrared spectroscopy, the good dispersion of GO in the matrix and the intrinsic properties of GO nanoplatelets. The strong and bioactive PCL/GO nanofibrous membranes with a high porosity have great potential for biomedical applications.