Search results for " nanocomposite"
showing 10 items of 199 documents
Time-resolved rheology as a tool to monitor the progress of polymer degradation in the melt state – Part II: Thermal and thermo-oxidative degradation…
2015
Abstract Thermal and thermo-oxidative degradation of nanocomposites based on polyamide 11 (PA11) and organo-modified clay (Cloisite® 30B) are studied in the melt state (T = 215 °C) via time-resolved mechanical spectroscopy (TRMS). The goal is assessing the potentiality of rheological analysis for studying polymer degradation in complex systems such as polymer nanocomposites, whose rheological response stems from the combination of the contributions of polymer and nanoparticles. We prove that a thorough analysis grounded on TRMS allows to isolate the effect of degradation of the polymer matrix, whose progress can be hence profitably monitored. Essentially the same degradation mechanisms as i…
Rheological and mechanical properties of biodegradable nanocomposites
2018
Polymer nanocomposites have gained huge interest over the last decade. However, traditional thermoplastic nanocomposites do not match the rising concern about environmental issues. Therefore, during the last years, the search for biodegradable polymer nanocomposites is gaining importance. Most of biobased (i.e. based on biodegradable/bioderived polymer matrices) nanocomposites have poly(lactic acid), PLA, as matrix. However, it is of clear interest to take into account also different biobased polymer matrices, such as MaterBi. In this work, we prepared bionanocomposites containing MaterBi or a PLA-based polymer matrix, with two different kinds of nanofillers (organomodified clay and nanosiz…
Influence of the modification, induced by zirconia nanoparticles, on the structure and properties of polycarbonate
2013
Melt compounding was used to prepare polycarbonate (PC)–zirconia nanocomposites with different amounts of zirconia. The effect of the zirconia loading, in the range of 1–5 wt.%, on the structure, mechanical properties and thermal degradation kinetics was investigated. The zirconia nanoparticle aggregates were well dispersed in the PC matrix and induced the appearance of a local lamellar order in the polycarbonate as inferred by SAXS findings. This order could be a consequence of the intermolecular interactions between zirconia and the polymer, in particular with the quaternary carbon bonded to the methyl groups and the methyl carbon as inferred from the NMR results. The presence of zirconia…
Polyisoprene-carbon black nanocomposites as tensile strain and pressure sensor materials
2004
Abstract Electrically conductive polymer composites (ECPC) are shown as prospective large-size flexible pressure and stretch sensors for detecting of dangerous deformations and vibrations of vehicle parts. Reversible change of resistance dependent on stretch and pressure is obtained in electro-conductive polymer nanocomposites. At certain concentrations of carbon nano-particles a change of electrical resistance by more than four orders is observed at 40% relative stretch. The maximum sensitivity of nanocomposites is observed in the vicinity of the transition of electro-conductive percolation. Nanocomposites exhibit a very weak semiconductor-like temperature dependence of resistance. The ten…
Recycling and Thermomechanical Degradation of LDPE/Modified Clay Nanocomposites
2013
The special features of polymer nanocomposites are continually gaining interest both in academia and in industry. The latter is especially experiencing an increase in interest towards this class of polymer composites, and this is leading to the first concerns about their reprocessing and reciclability. Here, a systematic study on the behavior of LDPE/Cloisite 15A systems upon reprocessing in a single-screw extruder is described, focusing on rheological, mechanical, and morphological properties changes. The investigated systems show a very complex thermomechanical degradation behavior, with the degradation of the clay modifier and different degradation paths involving the polymer matrix; all…
Modeling and stress-strain characteristics of the mechanical properties of carbon-nanotube-reinforced poly(vinyl acetate) nanocomposites
2011
Polymer/carbon nanotube (CNT) composites are one of the most perspective advanced materials developed in recent years. The properties of CNT-reinforced polymer composites, however, strongly depend on structural aspects of the nanostructured filler and on its dispersion quality in a polymer matrix. Consequently, this research was devoted to the investigation of multiwalled-CNT-modified poly(vinyl acetate) (PVAc) composites with respect to the mechanical property dependence on some structural characteristics of CNTs. PVAc/CNT nanocomposites were obtained with a solution casting technique. The amount of CNTs was changed from 0.01 up to 2 wt %. The stress–strain characteristics of PVAc/CNT nano…
Effect of an organoclay on the photochemical transformations of a PBAT/PLA blend and morpho-chemical features of crosslinked networks
2021
Abstract In this work, we report the effect of an organoclay on the photochemical weathering of nanocomposites based on a poly(butylene adipate-co-terephthalate) (PBAT)/poly(lactic acid) (PLA) blend. The evolution of physicochemical properties was monitored by integrating spectroscopic, mechanical, and morphological analyses. A robust relationship was found between the molecular transformations of the polymer macromolecules and the morpho-mechanical properties of irradiated films. Moreover, the analysis of insoluble fractions extracted from nanocomposites pointed out that free-standing, porous structures, displaying an unprecedented thickness as great as 100 µm, were formed, thus unambiguou…
Compatibilization of polyethylene/polyamide 6 blend nanocomposite films
2015
Polymer blends of incompatible components need to undergo compatibilization, in order to give rise to a blend with good physical properties. At the same way, polymer/clay nanocomposites show this problem because of different chemical nature of the polymer matrix and of the clay. Compatibilization is therefore more necessary if an incompatible polymer blend is filled with an organomodified clay in order to give a final material with good properties. In this work, a polyethylene/polyamide 6 blend filled with an organomodified clay has been compatibilized with a maleic anhydride grafted SEBS (styrene-ethylene-butylene-styrene) copolymer and a glicidylmethacrylate-ethylene copolymer. The result…
Limits of the linear viscoelastic behaviour of polyamide 66 filled with TiO2 nanoparticles: Effect of strain rate, temperature, and moisture
2008
Abstract Limits of linear viscoelastic behaviour of TiO 2 nanoparticle-filled polyamides are estimated quantitatively by the results of uniaxial tension tests. The stress limit of the filled polymer is higher than that of the un-filled one. Their values are the lower, the higher the temperature and moisture content of test specimens, and the lower, the lower the strain rate. The concept of an energy threshold for the linear viscoelastic behaviour is used to comprehensively characterize the limits over a wide range of test conditions. The energy limit is not affected by the strain rate, temperature, or moisture, and its value for the filled polymer is higher than that for the un-filled one. …
Prediction of the morphology of polymer-clay nanocomposites
2015
Abstract Polymer nanocomposites have continually attracted increasing interest over the last decade, due to significant improvements they can offer compared to neat polymer matrices. However, the final morphology of a nanocomposite, determined by several variables, can significantly influence the macroscopic properties of the final product. Therefore, it is important to study the interactions between processing, morphology, structure and rheological properties, and the suitability of existing models in order to predict the system's behaviour with change of the main processing variables. In this work, the applicability of a predictive theory based on the Wu model was formulated and proposed …