Graphene/polyurethane composites: fabrication and evaluation of electrical conductivity, mechanical properties and cell viability

Despite wide applications of reduced graphene-oxide (GO)-reinforced polymer-based composites, the necessity of the reduction procedure toward GO is still controversial. In this article, thermoplastic polyurethane (TPU) composites incorporated with GO and thermally reduced graphene oxide (TGO) were fabricated. GO and TGO exhibited different effects on crystallization behaviors, and mechanical and thermal properties of the TPU matrix. With 2.0 wt % filler loading, TPU composite reinforced by GO (TPU-GO-2 wt %) exhibited better thermal stability than that reinforced by TGO (TPU-TGO-2 wt %). The interfacial interaction between the nanofillers and the TPU matrix as well as their influence on the mobility of TPU chains were investigated, which proved that GO is superior to TGO in improving interface adhesion and maintaining crystallization of the TPU matrix. Compared with TPU-TGO-2 wt %, improved mechanical properties of TPU-GO-2 wt % were also evidenced owing to more oxygen-containing groups. This work demonstrates that the reduction of GO is not always necessary in fabricating polymer composites.

Section: Resultsmentioning

confidence: 99%

A comparison of thermoplastic polyurethane incorporated with graphene oxide and thermally reduced graphene oxide: Reduction is not always necessary

Wang

Chen

Zhu

et al. 2019

“…For better comparison with the classical percolation theory, the composites with 1.50 and 2.50 wt % GNS were further prepared and tested by four points probe method. A rapid increase in the electrical conductivity of composite materials after 0.75 wt % GNS content takes place when the conductive filler forms a conductive network of connected paths through the insulating matrix . The conductivity of the composites reaches a maximum of 0.058 S m −1 at 3.00 wt %.…”

Section: Resultsmentioning

confidence: 99%

Graphene nanosheets‐filled epoxy composites prepared by a fast dispersion method

Zhang

2017

Graphene nanosheets‐filled epoxy composites (GNS/Epoxy) were prepared at different filler loading levels from 0.25 to 3.00 wt %. A fast dispersion method as short as 5 min is employed to disperse GNS in epoxy matrix, which was enough for the homogeneous dispersion of GNS with the help of high ultrasonic frequency of 100 kHz and power of 200 W and high heat treatment temperature of 70 °C. The maximum electrical conductivity and thermal conductivity of the composites achieved 0.058 S m−1 and 0.57 W m−1 K−1, respectively, with a low electrical percolation threshold of 1.50 wt %. The electrical conductivities were further predicted by percolation theory and found to agree well with the experimental results, which indicated that the graphene nanosheets dispersed very well in the matrix even at very short processing time. The results showed that the microstructures, thermal, electrical, and mechanical properties of epoxy polymer were significantly improved by adding a low amount of graphene nanosheets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45152.

“…It is well‐known that properties such as stiffness, strength, thermal and electrical conductivity can be improved by addition of low amounts of nanofillers such as nanoclays, cellulose nanocrystals, graphene, graphene oxide (GO), and carbon nanotubes (CNTs) …”

Section: Introductionmentioning

confidence: 99%

Synthesis of CNT‐polyurethane nanocomposites using ester‐based polyols with different molecular structure: Mechanical, thermal, and electrical properties

Shamsi

Mahyari

Koosha

2016

Polyurethanes (PUs) were prepared by in situ polymerization of three diisocyanate with three synthesized low cost esterbased polyols. The effect of diisocyanate type, diol structure, and molar ratio of diisocyanate to polyol on the mechanical properties was examined and the optimum chemical structure was introduced regarding the superior mechanical properties. Also, in presence of well dispersed hydroxylated multiwalled carbon nanotubes (CNT), PU/CNT nanocomposites were synthesized and fully characterized. The results showed that PU synthesized based on 1,4-butane diol (BDO) has the best mechanical properties and thermal stability. Also, the PU samples synthesized from 1,6-hexamethylene diisocyanate (HDI) were more profitable than aromatic diisocyanate structures due to higher crystallinity and microstructure packing. The nanocomposite sample containing 1.5% CNT was the optimum composition for the maximum tensile strength and electrical conductivity. This result was related to the uniform dispersion and bonding of CNTs to PU chains at this composition, while aggregates were formed at higher concentration of CNTs which increased the defects and reduced the uniformity of the structure.