No abstract

Flexible energy storage devices are in great demand since the advent of flexible electronics. Until now, flexible supercapacitors based on graphene analogues usually have had low operating potential windows. To this end, two dissimilar electrode materials with complementary potential ranges are employed to obtain an optimum cell voltage of 1.8 V. A low-temperature organic sol-gel method is used to prepare two different types of functionalized reduced graphene oxide aerogels (rGOA) where Ag nanorod functionalized rGOA acts as a negative electrode while polyaniline nanotube functionalized rGOA acts as a positive electrode. Both materials comprehensively exploit their unique properties to produce a device that has high energy and power densities. An assembled all-solid-state asymmetric supercapacitor gives a high energy density of 52.85 W h kg and power density of 31.5 kW kg with excellent cycling and temperature stability. The device also performs extraordinarily well under different bending conditions, suggesting its potential to meet the requirements for flexible electronics.

In this article, we have developed sunflower oil based non‐isocyanate polyurethane (NIPU)/amine functionalized multiwalled carbon nanotube (AF‐CNT) composites. First, carbonated sunflower oil (CSFO) was obtained by solvent‐free mixture reaction of CO2 with epoxidized sunflower oil under the conditions (120°C, 40 bar) for 10 h, and characterized by FTIR, 1H NMR and 13C NMR. Then, NIPUs were synthesized by reacting the CSFO with isophorone diamine (IPDA) and subsequently, the effects of different weight percentages (0–2 wt%) of AF‐CNTs on physico‐chemical properties of the NIPU/AF‐CNT composites were examined. FT‐IR, XRD and SEM analyses confirmed the formation of the polymer nanocomposites. The results of the studies showed that polymer nanocomposites exhibited better performance than that of pristine polymer. In addition to the improvement in physico‐chemical properties, the electromagnetic interference shielding properties of the composites (1.5 wt% AF‐CNTs) were also calculated in the 8.2–12.4 GHz (X‐band) frequency range with different thicknesses. It is seen that the composite (1.5 wt%) with thickness 3 mm shows the highest microwave absorption with −17 dB at 10.86 GHz. POLYM. COMPOS., 40:E1120–E1130, 2019. © 2018 Society of Plastics Engineers

We developed a series of sunflower oil‐based non‐isocyanate polyurethane (NIPU)‐blend‐epoxy hybrid materials (HNIPUs) and their nanocomposites with amine‐functionalized graphene oxide (AF‐GO). Firstly, carbonated sunflower oil (CSFO) containing five‐membered cyclocarbonate groups was synthesized by the reaction of epoxidized sunflower oil with carbon dioxide (CO2) at a pressure of 50 bar and temperature of 110 °C. Then, a series of HNIPUs were synthesized using a mixture of CSFO and a commercially available epoxy resin in various amounts (10, 20 and 30 wt% with respect to CSFO) using isophorone diamine as the curing agent. The HNIPU with 30 wt% epoxy showed the best mechanical properties. Finally, nanocomposites of 30 wt% HNIPU‐based composition were prepared with various amounts of AF‐GO (0.3, 0.6 and 1.0 wt%) and were characterized using Fourier transform infrared and 1H NMR spectroscopies, X‐ray diffraction and scanning electron microscopy. These results emphasize the potentiality of this environmentally friendly approach for preparing renewable HNIPU and nanocomposite materials of high performances. © 2018 Society of Chemical Industry

No abstract