Ricerc@Sapienza

Widespread production and use of engineered nanomaterials in industrial and research settings raise concerns about their health impact in the workplace. In the last years, graphene-based nanomaterials have gained particular interest in many application fields. Among them, graphene nanoplatelets (GNPs) showed superior electrical, optical and thermal properties, low-cost and availability. Few and conflicting results have been reported about toxicity and potential effects on workers’ health, during the production and handling of these nanostructures.

In this work a simple cost-effective process is described to obtain a highly piezoresistive coating, consisting of sprayable water-based polyurethane (PU) paint filled with graphene nanoplatelets (GNPs). We investigated the morphology of the produced nanomaterials (i.e. cross-section and top surface) using a Field Emission Scanning Electron Microscope (FE-SEM). The rheological features of the polymeric blend loaded with 3.5 wt% of GNPs were analyzed at different concentrations of water (up to 20 wt%) in order to achieve a viscosity suitable for air-spraying.

This article presents a comparative review of the most commonly used nano-additives for bituminous mixtures: nanoclays (NC), nanosilicates, carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), nano-calcium oxide (CaO), and nano-titanium dioxide (TiO2). In this study, the mechanical behavior of the obtained additive mixture is evaluated. According to the revised literature, the results strongly depend on type, concentration, and dispersal of used nano-additive.

In the design of innovative nanomaterials for electromagnetic (EM) field absorption and shielding a crucial issue is the experimental characterization of the complex effective permittivity of non-uniform layered materials or electrically thin lossy layers. This paper proposes a technique to retrieve the complex relative permittivity of a thin lossy coating supported by a dielectric substrate through transmission/reflection measurements in a rectangular waveguide.

The development of lightweight microwave absorber, operating in a wide range of frequencies, is still a challenging task. A novel broadband lightweight radar absorbing material is developed using a phenolic aramid honeycomb (HC) coated with a graphene-filled polymeric paint, which is made of a colloidal suspension of graphene nanoplatelets (GNPs) dispersed in a mixture of polyvinyl-alcohol, water, and 1-propanol.

In this paper, we report our recent results on the preparation and characterization of biocompatible nanocomposites made of a silicone-based polymer matrix with tunable elasticity (polydimethylsiloxane, PDMS, and its mixtures with hydroxyl-terminated PDMS) and DNA-functionalized graphene nanoplatelets as fillers. The aim is to exploit the biocompatible character and the high flexibility of the PDMS matrix, together with the exceptional mechanical strength, and good thermal and electrical conductivity of the graphene nanofillers (GNP) for applications in biomedical and sensing devices.

Filler dispersion in polymer matrices plays an important role in defining the performance of nanocomposite materials. Here, a novel method for the quantitative assessment of filler dispersion is reported. The method is based on the direct analysis of optical images using an algorithm implemented in MATLAB, which considers the distance of each pixel with respect to pixels of same value and to pixels of different value. A dispersion index is determined by comparing the grayscale optical image with the corresponding uniformly dispersed image.

In additive manufacturing (3D printing) processes, polyethylene (PE) filaments can be taken into consideration build and recycle components in space, thus reducing costs, risks, and logistics issues that can occur during a long-term mission beyond Low Earth Orbits. In fact, the excellent radiation shielding properties of polyethylene, which are due to its high content of hydrogen, have found consensus among the scientific community. On the other hand, PE shows poor mechanical, electrical, and thermal properties.