Molecular Junctions between Graphene Nanoplatelets to Enhance Heat Transfer in Nanomaterials / BE... more Molecular Junctions between Graphene Nanoplatelets to Enhance Heat Transfer in Nanomaterials / BERNAL ORTEGA, MARIA DEL MAR; Ferraro, Giuseppe; Eleuteri, Matteo; DI PIERRO, Alessandro; Fina, Alberto. ELETTRONICO. (2018). ((Intervento presentato al convegno Graphene2018 tenutosi a Dresden (Germany) nel 26-29 June 2018. Original Molecular Junctions between Graphene Nanoplatelets to Enhance Heat Transfer in Nanomaterials
As the exploitation of graphene in materials for large scale application is still very much limit... more As the exploitation of graphene in materials for large scale application is still very much limited by the amount and quality of graphenes available, for large scale bulk applications in polymer nanocomposites, multilayer graphenes or graphene nanoplatelets (GNP) are currently the most interesting graphenebased materials. Thermal conductivities for graphenes were reported in the wide range of about 1500 to 6000 W/mK; however, thermal properties of graphene-based materials may decrease dramatically as a function of the number of layers, the density of topological defects, re-hybridization defects as well as on the presence of impurities. In this paper, different types of GNPs were thoroughly characterized both in terms of chemical/physical properties and in terms of thermal properties of individual flakes. Two selected GNPs were annealed at 1700°C in vacuum for 1 h to reduce defectivity of the graphenic structure, evidencing that thermal annealing can considerably reduce the amount o...
Nanocomposites from native cellulose with low 2D nanoplatelet content are of interest as sustaina... more Nanocomposites from native cellulose with low 2D nanoplatelet content are of interest as sustainable materials combining functional and structural performance.
The aim of this work was to develop an effective approach to improve the graphite dispersion and,... more The aim of this work was to develop an effective approach to improve the graphite dispersion and, consequently, the electrical conductivity of nanocomposites based on polycaprolactone (PCL) and graphite nanoplates (GNP). With this aim, a polymeric additive was designed to be compatible with the polymer matrix and capable of interacting with the graphite layers. Indeed, the compound consists of a low molecular mass PCL ending with a pyrene group (Pyr-PCL). The exploitation of such a molecule is expected to promote from one side specific interactions of the pyrene terminal group with the surface of graphite layers and from the other to guarantee the compatibility with PCL, having a chain with the same nature as the matrix. The features of the nanocomposites prepared by directly blending PCL with GNP were compared with those of the same systems also containing the additive. Moreover, a neat mixture, based on PCL and PCL-Pyr, was prepared and characterized. The specific interactions bet...
In this study, we report a novel strategy to prepare graphene nanopapers from direct vacuum filtr... more In this study, we report a novel strategy to prepare graphene nanopapers from direct vacuum filtration. Instead of the conventional method, i.e., thermal annealing nanopapers at extremely high temperatures prepared from graphene oxide (GO) or partially reduced GO, we fabricate our graphene nanopapers directly from suspensions of fully reduced graphene oxide (RGO), obtained after RGO and thermal annealing at 1700 °C in vacuum. By using this approach, we studied the effect of thermal annealing on the physical properties of the macroscopic graphene-based papers. Indeed, we demonstrated that the enhancement of the thermal and electrical properties of graphene nanopapers prepared from annealed RGO is strongly influenced by the absence of oxygen functionalities and the morphology of the nanoflakes. Hence, our methodology can be considered as a valid alternative to the classical approach.
ABSTRACT An experimental setup was proposed for evaluating the thermal shielding efficiency of in... more ABSTRACT An experimental setup was proposed for evaluating the thermal shielding efficiency of intumescent coatings. In particular, a cone calorimeter as heater source was coupled with a thermocouple as detector of the temperature of steel plates coated with intumescent coatings. According to ENV 13381-4 test procedure, the heating curves of the setup was measured by plate thermocouple and compared with ISO 834 standard curve. Meanwhile, the comparison was also made between temperature profiles of blank steel plates at different heat fluxes and unprotected steel elements under ISO fire. The possible correlation between bench scale and large scale test was hence discussed. Several factors (heat flux, distance to cone heater, coating thickness, sample size, edge effect and heat insulator) were deeply investigated and discussed: significant relationships between these parameters and the thermal protective properties of the intumescent coating were evidenced; furthermore a fully developed intumescent char could be obtained by controlling the aforementioned parameters. As a conclusion, the proposed bench-scale test was found to be comparable to the large scale test only in the early heating stages.
Molecular Junctions between Graphene Nanoplatelets to Enhance Heat Transfer in Nanomaterials / BE... more Molecular Junctions between Graphene Nanoplatelets to Enhance Heat Transfer in Nanomaterials / BERNAL ORTEGA, MARIA DEL MAR; Ferraro, Giuseppe; Eleuteri, Matteo; DI PIERRO, Alessandro; Fina, Alberto. ELETTRONICO. (2018). ((Intervento presentato al convegno Graphene2018 tenutosi a Dresden (Germany) nel 26-29 June 2018. Original Molecular Junctions between Graphene Nanoplatelets to Enhance Heat Transfer in Nanomaterials
As the exploitation of graphene in materials for large scale application is still very much limit... more As the exploitation of graphene in materials for large scale application is still very much limited by the amount and quality of graphenes available, for large scale bulk applications in polymer nanocomposites, multilayer graphenes or graphene nanoplatelets (GNP) are currently the most interesting graphenebased materials. Thermal conductivities for graphenes were reported in the wide range of about 1500 to 6000 W/mK; however, thermal properties of graphene-based materials may decrease dramatically as a function of the number of layers, the density of topological defects, re-hybridization defects as well as on the presence of impurities. In this paper, different types of GNPs were thoroughly characterized both in terms of chemical/physical properties and in terms of thermal properties of individual flakes. Two selected GNPs were annealed at 1700°C in vacuum for 1 h to reduce defectivity of the graphenic structure, evidencing that thermal annealing can considerably reduce the amount o...
Nanocomposites from native cellulose with low 2D nanoplatelet content are of interest as sustaina... more Nanocomposites from native cellulose with low 2D nanoplatelet content are of interest as sustainable materials combining functional and structural performance.
The aim of this work was to develop an effective approach to improve the graphite dispersion and,... more The aim of this work was to develop an effective approach to improve the graphite dispersion and, consequently, the electrical conductivity of nanocomposites based on polycaprolactone (PCL) and graphite nanoplates (GNP). With this aim, a polymeric additive was designed to be compatible with the polymer matrix and capable of interacting with the graphite layers. Indeed, the compound consists of a low molecular mass PCL ending with a pyrene group (Pyr-PCL). The exploitation of such a molecule is expected to promote from one side specific interactions of the pyrene terminal group with the surface of graphite layers and from the other to guarantee the compatibility with PCL, having a chain with the same nature as the matrix. The features of the nanocomposites prepared by directly blending PCL with GNP were compared with those of the same systems also containing the additive. Moreover, a neat mixture, based on PCL and PCL-Pyr, was prepared and characterized. The specific interactions bet...
In this study, we report a novel strategy to prepare graphene nanopapers from direct vacuum filtr... more In this study, we report a novel strategy to prepare graphene nanopapers from direct vacuum filtration. Instead of the conventional method, i.e., thermal annealing nanopapers at extremely high temperatures prepared from graphene oxide (GO) or partially reduced GO, we fabricate our graphene nanopapers directly from suspensions of fully reduced graphene oxide (RGO), obtained after RGO and thermal annealing at 1700 °C in vacuum. By using this approach, we studied the effect of thermal annealing on the physical properties of the macroscopic graphene-based papers. Indeed, we demonstrated that the enhancement of the thermal and electrical properties of graphene nanopapers prepared from annealed RGO is strongly influenced by the absence of oxygen functionalities and the morphology of the nanoflakes. Hence, our methodology can be considered as a valid alternative to the classical approach.
ABSTRACT An experimental setup was proposed for evaluating the thermal shielding efficiency of in... more ABSTRACT An experimental setup was proposed for evaluating the thermal shielding efficiency of intumescent coatings. In particular, a cone calorimeter as heater source was coupled with a thermocouple as detector of the temperature of steel plates coated with intumescent coatings. According to ENV 13381-4 test procedure, the heating curves of the setup was measured by plate thermocouple and compared with ISO 834 standard curve. Meanwhile, the comparison was also made between temperature profiles of blank steel plates at different heat fluxes and unprotected steel elements under ISO fire. The possible correlation between bench scale and large scale test was hence discussed. Several factors (heat flux, distance to cone heater, coating thickness, sample size, edge effect and heat insulator) were deeply investigated and discussed: significant relationships between these parameters and the thermal protective properties of the intumescent coating were evidenced; furthermore a fully developed intumescent char could be obtained by controlling the aforementioned parameters. As a conclusion, the proposed bench-scale test was found to be comparable to the large scale test only in the early heating stages.
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