The synthesis of new composite nanomaterials based on graphene oxide (GO)modified with cellulose and its derivatives, as well as nanocellulose, is currently an important direction and contributes toward solving many problems in various fields such as nanotechnology, information technology, medicine, high-dielectric materials, and nanoelectronics. In this work, for the first time, for the production of GO and its membrane with carboxymethylcellulose (CMC), local Kazakhstan “Ognevsky” graphite was used as the initial raw material. In this regard, the preparation of nanocomposites of GO modified with cellulose derivatives, including CMC, attracts great interest from scientists and expands its field of practical application due to the significant changes in its physicochemical properties. In this work, the GO obtained using the Hummers method was modified by CMC, and its physicochemical, structural, and electrical characteristics were studied. The GO/CMC membrane was synthesized by mixing 1% GO with crushed solid mass of CMC (0.03 g; 0.06 g; 0.15 g) and then processing using ultrasound. The surface morphology of the GO/CMC membrane was studied using scanning electron microscopy (SEM). It has been established that by increasing the mass of CMC (0.03 g; 0.06 g; 0.15 g), the polymerization of CMC occurs on the surface of GO nanosheets. Cross-sectional micrographs of GO/CMC show the formation of sandwich-like layered structures. The synthesis efficiency (yield) of GO from synthetic graphite is 10.8%, and GO from Ognevsky graphite is 11.9%, almost 1.1% more than GO from synthetic graphite. The mechanical tensile strength increases from 2.3 MPa to 14.3 MPa and the Young’s modulus from 2.3 MPa to 143 MPa. The electrical parameters of the humidity sensor based on GO and GO/CMC membranes (0.03 g; 0.06 g; 0.15 g) were studied as a function of humidity to determine the performance of the device.

Transforming local Kazakhstan graphite into high-quality GO and RGO, exploring their properties for future applications in optoelectronics and sensors.

Intensive research of nanocomposites contributes to the development of new materials in the fields of medicine, nanoelectronics, energy, biotechnology, information technology. Therefore, the synthesis of new materials by modifying of graphene oxide (GO) with nanocellulose and the study of its properties are of great interest. In this study synthesized nanocomposite material by modifying of graphene oxide (GO) from activated carbon (BAU-A) in a 1:1 volume ratio with nanocellulose (NC) from hemp stems belonging to the annual plant, and their chemical structure was studied by FTIR and UV-spectroscopy. The results of the study showed the absorption of the etheric bond C = O in the UV spectrum at full length 243 nm. The IR spectrum showed all the new etheric bonds O = C - OH at a wavelength of 1625 cm^-1. The average particle sizes of GO was 352 nm and NC was 470 nm in length and 80 nm in width. The SEM analysis indicating the NC as a contact layer between ultralow thicknesses of the GO layers. The XRD analysis indicated GO-NC composite film is a substance comprising GO and NC. According to the results, modification of graphene oxide showed that its scope can be expanded as much as possible.

This article is devoted to the study of microwave-absorbing properties of Co-C coating applied by magnetron sputtering. This article presents the main results of the manufacturing of a Co-C coating by magnetron sputtering, and the evaluation of experimental and computational research data on the relationship between the structure and properties of the obtained films. The structure of Co-C systems has been modeled to control the resulting structures using X-ray diffraction analysis. The structural-phase state of the resulting thin-film Co-C systems and the microwave-absorbing properties of coatings were studied using the transmission line method, consisting of a vector network analyzer, an air coaxial line, a software program, and an external computer. It has been established that on the resulting Co-C film the reflection coefficient in the frequency range of 8.2–12.4 GHz varies in the range of 900 → 718 mU, with reflection losses of −0.86 → −2.57 dB, and a standing wave coefficient of 19 → 6.8. An analysis of the obtained data indicates the presence of losses of electromagnetic energy in the studied frequency range.

Currently, one of the topical directions in the field of production and application of graphene-like nanostructures is the use of renewable natural raw materials, which have unlimited resources for an economically efficient large-scale yield of a product with environmental safety. In this regard, we present the production of graphene oxide (GO) from a renewable natural raw material of plant biomass, birch activated carbon (BAC), and a comparison of the obtained physicochemical, mechanical, and electrical properties of birch activated carbon–graphene oxide (BAC–GO) and graphite–graphene oxide (G–GO) synthesized from the initial materials, BAC and graphite (G). Results obtained from this study confirm the successful oxidation of BAC, which correlates well with the physical–chemical dates of the G–GO and BAC–GO samples. Change in data after the oxidation of graphite and BAC was facilitated by the structure of the starting materials and, presumably, the location and content of functional oxygen-containing groups in the G–GO and BAC–GO chains. Based on the results, the application of a cost-effective, eco-friendly colloidal solution of nanodispersed BAC–GO from a plant biomass-based high-quality resource for producing large-scale nanostructured graphene is validated which has potential applicability in nanoelectronics, medicine, and other fields.