Polymer nanocomposite

About: Polymer nanocomposite is a research topic. Over the lifetime, 8977 publications have been published within this topic receiving 297599 citations.

Dielectric relaxation behaviour in semi-crystalline polyvinylidene fluoride (PVDF)/TiO2 nanocomposites

Abstract: Polymer nanocomposites based on polyvinylidene fluoride (PVDF) matrix filled with TiO 2 nanoparticles (1%, 2%, 3% and 5% by v/v%) were studied by broadband dielectric spectroscopy (BDS) in order to investigate the filler effect on the molecular mobility of the polymer chains. The formalism of electric modulus was used to analyze the dielectric response, thus three relaxation processes were observed. In fact, the first one, which is around −40 °C at 10 Hz, is attributed to the glass transition at low temperature. As for the second phenomenon, around 30 °C at 10 Hz, it is related to the dipolar relaxations in the crystalline phase. Regarding the third one, around 100 °C at 10 Hz, it can be due to the interfacial polarization (IP). The crystallinity ratio decreases and the electric modulus of the interfacial polarization increases with the increase of the TiO 2 content.

New Method To Prepare Graphite Nanocomposites

Abstract: A novel processing technique to fabricate graphene-based polymer nanocomposites via sulfur/graphite composite was developed. First, the sulfur/graphite composite was prepared, where sulfur nanoparticles were dispersed on the surfaces of graphenes. This was subsequently used to prepare polymer/graphite nanocomposites by the melt mixing method.

Enhanced stiffness of amorphous polymer surfaces under confinement of localized contact loads

Abstract: Although there is an increasing appreciation that physical properties of amorphous (glassy) polymer surfaces and interfaces can differ substantially from those of the bulk, the mechanisms and implications for mechanical performance of thin films, surfaces of bulk polymers, and nanocomposites are unclear. For example, several natural and synthetic nanocomposites exhibit markedly enhanced stiffness and strength that cannot be explained via two-phase composite rules-of-mixtures. Here we apply recent advances in contact deformation to determine the apparent elastic (or storage) moduli over 5 to 200 nanometers from the free surface of amorphous polystyrene, poly(methyl methacrylate), and polycarbonate. We observe that the apparent stiffness of the surface under contact can exceed that of the bulk by up to 200%, independent of processing scheme, macromolecular structural characteristics, and relative humidity. We attribute this enhanced apparent stiffness at the surface to the contact stress-induced formation of a mechanically confined phase at the probepolymer interface. These observations are consistent with the increased macromolecular mobility of glassy polymer free surfaces, and relate directly to the material physics of the interphase in synthetic and biological polymer nanocomposites. Most experimental investigations of amorphous polymer surfaces have focused on thermally activated behavior such as the glass transition temperature Tg [1–3] and structural relaxation. [4,5] However, few overarching conclusions exist regarding surface and interface properties, [6] in large part because ex