CARBON NANOSTRUCTURES OBTAINING FROM POLYMER MATERIALS

Abstract

As part of the expansion of raw material base used in the development of technological and productive methods for the synthesis of carbon nanostructures (CNS) and solving the problem of environmentally friendly and economical polymer recycling, the results of investigation of microwave (MW) catalytic pyrolysis of macromolecular compounds from the range of polystyrene, polypropylene, polyethylene terephthalate, polyvinyl alcohol are presented. The information about existing approaches to solving these problems is briefly considered, and the prospects for MW processing of polymers are shown. The process was carried out by microwave treatment of a mixture of polymer raw materials acting as a carbon donor and substances-precursors of metal catalysts – cobalt and nickel compounds, their mixtures, as well as metal iron and nickel. Graphite and carbon fiber were used as temperature regulator. Experiments have demonstrated that effective conversion of the studied compounds occurs only in the presence of MW energy absorbers-converters, regardless of the nature of metal catalyst precursor. According to electron microscopy data, the resulting materials are a mixture of carbon nanostructures of disordered morphology with the predominant content of carbon nanotubes (CNTs) in the reaction products for experiments with polystyrene, polypropylene and polyethylene terephthalate. The use of polypropylene and polyvinyl alcohol leads to the production of carbon nanostructures containing only a small amount of CNTs. X-ray phase analysis data confirm the formation of multi-walled carbon nanotubes as the main structural component of the obtained carbon nanomaterials. It has been suggested that transformation pathways of the investigated hydrocarbons are similar, despite the difference in pyrolysis temperatures, which may be related to the simultaneous processes of polymer cracking, carbonization of decomposition products and CNS synthesis due to the rapid growth of reaction mass temperature during microwave treatment. The efficiency of different precursors of catalytic systems based on transition metals in the processes examined is substantiated. It has been shown that the high carbon content in feedstock promotes the formation of carbon nanostructures, but is not decisive for carbon nanotubes obtaining. For citation: Zaritovskii A.N., Kotenko E.N., Grishchuk S.V. Carbon nanostructures obtaining from polymer materials. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 99-106. DOI: 10.6060/ivkkt.20246705.6957.