الفهرس | Only 14 pages are availabe for public view |
Abstract The aim of this study is developing graphene/polyamide12 nanocomposites of good mechanical performance as light-weight structural materials for structural applications that demand (rigidity and light weight) such as, automotive, aerospace, and wind turbine technologies. A new facile approach for the gram-scale synthesis of powdery graphene nanoplatelets from glucose precursor has been developed. This approach involves one-step hydrothermal treatment of glucose in presence of few milliliters of ammonia, followed by moderate temperature thermal annealing under the inert atmosphere. Firstly, reduced graphene oxide (RGO) has been prepared in gram-scale via hydrothermal treatment of glucose. Upon increasing the vapor/liquid ratio for aqueous glucose solution within the autoclave system to 3/2, RGO3/2 -rich graphitic powder, containing small graphene oxide and amorphous carbon contents and having a spherical morphology, is obtained. Then, the effect of chemical reagent/s combined with glucose within the autoclave system has been studied (by introducing of few milliliters of ammonia, ammonia-hydrazine hydrate mixture, HCl and NaOH into the reaction medium). It is found that the number of H+, produced from the evolved byproduct hydrogen gas, has a vital role in deoxygenating the aromatic sp2 domains constituting the graphitic structure. The analyses reveal that increasing the number of evolved H+ leads to the formation of less oxidized graphitic structure. The number of evolved H+ is produced from the reagents in the following order: HCl then ammonia and the maximum number is produced from the ammonia-hydrazine mixture. On the other hand, it is found that NaOH does not produce any proton. Besides, the evolved nitrogen gas produced from ammonia and ammonia-hydrazine creates fitted inert atmosphere to cope any oxygenation process. Accordingly, hydrothermally graphitic powder resulted from the addition of ammonia-hydrazine mixture, Amm-Hyz- RGO3/2, represents the RGO sample of the best structural quality among all the hydrothermally produced graphitic samples with minimum O and amorphous carbon contents and best structural order interior of the aromatic sp2 domains. Actually, the quality of the hydrothermally graphitic sample resulted from the addition of ammonia, Amm-RGO3/2 is nearby to that of the Amm-Hyz-RGO3/2. However, Amm-RGO3/2 formed significantly in larger yield than Amm-Hyz-RGO3/2. Moreover, a flat iii nanoplatelets morphology has been confirmed for Amm-RGO3/2. Accordingly, Amm– RGO3/2 is considered to be the optimum sample, regarding the quality as well as the productivity. Afterward, RGO3/2 and Amm–RGO3/2 have been thermally. |