The mechanical properties of GNP/LDPE nanocomposites (graphite nanoplatelets/low density polyethylene) have been investigated, in order to establish the effect of nanoscale reinforcement within the polymer matrix. Results show that the presence of the filler does not involve a change in the microscopic structure of the polymer. However, on a macroscopic scale, GNPs limit the mobility of the polymer chains, resulting in an increase in stiffness for the final composite. Orientation of GNPs within the LDPE matrix is also an important issue that affects mechanical properties and it has been evaluated by testing nanocomposites made by different manufacturing techniques (compression moulding and blown extrusion). The comparison between the experimental data and the Halpin-Tsai model shows that the orientation of GNPs due to the extrusion process leads to values of tensile modulus higher than that obtained with the randomly oriented disposition resulting from the compression moulding technique.

An effective method of preparation of\ud bismuth nanopowders by thermal decomposition of\ud bismuth dodecyl-mercaptide Bi(SC12H25)3 and preliminary\ud results on their thermoelectric properties are\ud reported. The thermolysis process leads to Bi nanoparticles\ud due to the efficient capping agent effect of\ud the dodecyl-disulfide by-product, which strongly\ud bonds the surface of the Bi clusters, preventing their\ud aggregation and significantly reducing their growth\ud rate. The structure and morphology of the thermolysis\ud products were investigated by differential scanning\ud calorimetry, thermogravimetry, X-ray diffractometry,\ud 1H nuclear magnetic resonance spectroscopy, scanning\ud electron microscopy, and energy dispersive\ud spectroscopy. It has been shown that the prepared\ud Bi nanopowder consists of spherical shape nanoparticles,\ud with the average diameter depending on the\ud thermolysis temperature. The first results on the\ud thermoelectric characterization of the prepared Bi\ud nanopowders reveal a peculiar behavior characterized\ud by a semimetal–semiconductor transition, and a\ud significant increase in the Seebeck coefficient when\ud compared to bulk Bi in the case of the lowest grain\ud size (170 nm)

An advantageous micromechanical technique to deposit large area graphene nanoplatelet (GNP) thin films on a low-density polyethylene substrate is proposed. This method is based on the application of shear-stress and friction forces to a graphite platelets/ethanol paste on the surface of a polymeric substrate; it allows us to obtain a continuous film of superimposed nanoplatelets mainly made of 13-30 graphene layers. X-ray diffraction (XRD), atomic force and transmission electron microscopy (TEM) measurements support the occurrence of a partial exfoliation of the graphite platelets due to shear-stress and friction forces applied during film formation. Scanning electron microscopy (SEM) observations point out that the surface of the polymer is uniformly coated by the overlap of GNPs, and TEM analysis reveals the tendency of the nanoplatelets to align parallel to the interface plane. It has been found that the deposited samples, under white light illumination, exhibit a negative photoconductivity and a linear photoresponse as a function of the applied voltage and the optical power density in the -120 ÷ 120 mV and 20.9 ÷ 286.2 mW cm ranges, respectively.