Search results for " nanoplatelets"
showing 10 items of 17 documents
PLA graphene nanoplatelets nanocomposites: Physical properties and release kinetics of an antimicrobial agent
2017
Abstract Graphene nanoplatelets (GnP) as filler and ciprofloxacin (CFX) as biocide were incorporated via melt-compounding into poly(lactic acid) (PLA) to obtain biopolymer-based nanocomposites with antimicrobial properties. GnP were added with the aim of improving the mechanical properties of the antimicrobial system and tuning the drug release. The obtained systems were mechanically characterized in tensile mode by quasi-static and dynamic mechanical tests. Furthermore, rheological measurements were performed. The morphology of the samples was analyzed through scanning electron microscopy (SEM). Moreover, a mathematical model, i.e. power law model, was used to fit the release data in order…
Effect of Graphene Nanoplatelets on the Physical and Antimicrobial Properties of Biopolymer-Based Nanocomposites
2016
In this work, biopolymer-based nanocomposites with antimicrobial properties were prepared via melt-compounding. In particular, graphene nanoplatelets (GnPs) as fillers and an antibiotic, i.e., ciprofloxacin (CFX), as biocide were incorporated in a commercial biodegradable polymer blend of poly(lactic acid) (PLA) and a copolyester (BioFlex®). The prepared materials were characterized by scanning electron microscopy (SEM), and rheological and mechanical measurements. Moreover, the effect of GnPs on the antimicrobial properties and release kinetics of CFX was evaluated. The results indicated that the incorporation of GnPs increased the stiffness of the biopolymeric matrix and allowed for the t…
Colloidal Nanoplatelet/Conducting Polymer Hybrids: Excitonic And Material Properties
2016
WOS:000370678700053 Here we present the first account of conductive polymer/colloidal nanoplatelet hybrids. For this, we developed DEH-PPV-based polymers with two different anchor groups (sulfide and amine) acting as surfactants for CdSe nanoplatelets, which are atomically flat semiconductor nanocrystals. Hybridization of the polymers with the nanoplatelets in the solution phase was observed to cause strong photoluminescence quenching in both materials. Through steady-state photoluminescence and excitation spectrum measurements, photoluminescence quenching was shown to result from dominant exciton dissociation through charge transfer at the polymer/nanoplatelet interfaces that possess a sta…
Bottom-up realization and electrical characterization of a graphene-based device.
2016
We propose a bottom-up procedure to fabricate an easy-to-engineer graphene-based device, consisting of a microstrip-like circuit where few-layer graphene nanoplatelets are used to contact two copper electrodes. The graphene nanoplatelets are obtained by the microwave irradiation of intercalated graphite, i.e., an environmentally friendly, fast and low-cost procedure. The contact is created by a bottom-up process, driven by the application of a DC electrical field in the gap between the electrodes, yielding the formation of a graphene carpet. The electrical resistance of the device has been measured as a function of the gap length and device temperature. The possible use of this device as a …
Morphology, Rheological and Mechanical Properties of Isotropic and Anisotropic PP/rPET/GnP Nanocomposite Samples
2021
The effect of graphene nanoplatelets (GnPs) on the morphology, rheological, and mechanical properties of isotropic and anisotropic polypropylene (PP)/recycled polyethylene terephthalate (rPET)-based nanocomposite are reported. All the samples were prepared by melt mixing. PP/rPET and PP/rPET/GnP isotropic sheets were prepared by compression molding, whereas the anisotropic fibers were spun using a drawing module of a capillary viscometer. The results obtained showed that the viscosity of the blend is reduced by the presence of GnP due to the lubricating effect of the graphene platelets. However, the Cox–Merz rule is not respected. Compared to the PP/rPET blend, the GnP led to a slight incre…
Preferred Growth Direction by PbS Nanoplatelets Preserves Perovskite Infrared Light Harvesting for Stable, Reproducible, and Efficient Solar Cells
2020
Formamidinium-based perovskite solar cells (PSCs) present the maximum theoretical efficiency of the lead perovskite family. However, formamidinium perovskite exhibits significant degradation in air. The surface chemistry of PbS has been used to improve the formamidinium black phase stability. Here, the use of PbS nanoplatelets with (100) preferential crystal orientation is reported, to potentiate the repercussion on the crystal growth of perovskite grains and to improve the stability of the material and consequently of the solar cells. As a result, a vertical growth of perovskite grains, a stable current density of 23 mA cm(-2), and a stable incident photon to current efficiency in the infr…
Reprocessing of PLA/graphene nanoplatelets nanocomposites
2017
This work reports a study on the effect of multiple reprocessing on the properties of poly(lactic acid) (PLA) filled with graphene nanoplatelets (GnP) compared to the melt reprocessed neat polymeric matrix. In particular, morphological, X-Ray Diffraction and Micro-Raman analyses, intrinsic viscosity measurements, thermal, rheological and mechanical tests were carried out on materials reprocessed up five times by means of a single screw extruder. The results indicated that the presence of GnP decreased the degradation rate as a function of the reprocessing cycles in comparison with the neat PLA that, on the contrary, showed a more drastic reduction of the molecular weight. Moreover, the repr…
Effect of processing temperature and mixing time on the properties of PP/GnP nanocomposites
2020
Abstract During processing of molten polymers the thermal and mechanical stress acting on the melt in presence of oxygen can induce degradation with a modification of the chemical structure of the polymers. This picture can become even more relevant if the melt is a multiphasic polymer system. In this last case, the effects of the degradation depend also on the presence of a second phase and on the interactions between the two phases. In this work, the effect of the processing conditions, temperature and time, have been considered in order to investigate the thermo-mechanical and thermo-oxidative degradation of nanocomposites made by polypropylene and different contents of graphene nanoplat…
Photo-oxidation of polypropylene/graphene nanoplatelets composites
2019
Abstract The photo-oxidation behaviour of polymer nanocomposites depends not only on the photo-oxidation behaviour of the matrix, but also on the chemical composition, on the physical properties of the nanoparticles and on the possible interactions between the two phases. In the case of nanocomposites with carbonaceous particles, the main effect is a photo-stabilization due to the absorption of the UV energy and the radical scavenging action. In this work we investigated the effect of the presence of graphene nanoplatelets on the photo-oxidation behaviour of the polypropylene. The presence of the graphene nanoplatelets improves the photo-resistance of the polypropylene and this effect incre…
Thermomechanical degradation of PP based nanocomposites filled with graphene nanoplatelets
2018
Graphitic nanofillers have extensively used to prepare nanocomposites based on both conventional petroleum based plastics and bio-based polymers . Among them, graphene or graphite nanoplatelets (GnP), also called graphite nanosheets or nanoflakes, are a relatively new carbon nanomaterial composed of stacked 2D graphene sheets with outstanding electrical, thermal and mechanical properties. Indeed, by adding GnP, also at low filler concentration (< 5 wt.%), the mechanical, heat-resistance, thermal and electrical properties of the polymer matrix can surprisingly enhance due to unique properties of these nanofillers. However, the characteristics of these multiphase systems certainly depend o…