Search results for "composite"
showing 10 items of 4584 documents
Rheological Behaviour, Mechanical Properties and Processability of Biodegradable Polymer Systems for Film Blowing
2017
Films for agricultural or packaging applications are typically made of low density polyethylene (LDPE). They are produced through the film blowing process, which requires the use of polymers with suitable rheological properties. Furthermore, the short shelf-life which is often related to many packed products leads to huge amounts of plastic-based wastes. This suggests the use of biodegradable and/or compostable polymers in replacement for traditional ones. To this regard, only few data exist on the rheological properties of biodegradable polymers undergoing film blowing processing. In this work, a detailed investigation on the rheological, mechanical and processability behaviour of some bio…
Rheological Behavior Under Shear and Non-Isothermal Elongational Flow of Biodegradable Polymers for Foam Extrusion
2013
The production of many items, in particular for food packaging applications, is based on foam extrusion and thermoforming. These operations require the use of polymers which can grant some specific rheological properties, both under shear and elongational flow. In this work, the behavior of some biodegradable polymers [Mater-Bi® and poly(lactic acid)] under shear and non-isothermal elongational flow was investigated and compared with a traditional, non-biodegradable polymer, in order to assess their suitability for industrial-scale foam extrusion and thermoforming. The rheological characterization evidenced the differences between the different biodegradable polymers and the reference polys…
Mesoporous silica-based materials for use in electrochemical enzyme nanobiosensors
2012
Abstract Biology and medicine have seen great advancements in the development of enzyme nanobiosensors capable of characterizing and quantifying biomolecules. We provide an overview of mesoporous silica (MPS)-based enzyme nanobiosensors developed for biological and medical applications, and we describe significant advances in these technologies. We review progress in constructing high-performance electrochemical enzyme biosensors. We also discuss: • MCM-41 and SBA-15-modified and MPS composite electrodes for enzyme biosensing; • incorporation of biorecognition elements into MPS material electrodes for enzyme biosensing; and, • MCM-41 and SBA-15-supported electrocatalytic MPS-based electroch…
The anisotropic behaviour of a preoriented poly (ethylene terephthalate) during plastic deformations
1978
Data on the anisotropic tensile behavior of samples cut along several directions of a biaxially oriented PET sheet are here presented. Shear deformations were observed together with the usual elongations. The data are compared with the predictions of a non-linear model recently proposed.
Experimental Testing of Some Polymer Materials
2019
Abstract The research aims to test polymer materials as the plastic materials: UHMWPE and POM, to observe there characteristics, to determing how they can be used and what we can obtain from them. We wanted to see the strong and the weak values that characterize them, what kind of parts we can produce from them and in what case we can use it. By applying this tests is necessary in order to see real datas that can help you compare them, and lead you to conclusions. Using these methods of testing materials leads to the establishment of real properties of the material and to the establishment of new configurations necessary to be made to the manufactured parts.
Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer
2015
We present a structurally flexible copper–iodide–pyridine-based coordination polymer showing drastic variations in its electrical conductivity driven by temperature and sorption of acetic acid molecules. The dramatic effect on the electrical conductivity enables the fabrication of a simple and robust device for gas detection. X-ray diffraction studies and DFT calculations allow the rationalisation of these observations.
Space Charge Dynamics in Nanostructured Epoxy Resin
2008
The results of a comparative analysis performed on specimens of nanostructured epoxy resins obtained by different filler concentrations are reported in this paper. The specimens were prepared by dispersion of bohemite nanoparticles into a cycloaliphatic epoxy resin cross linked under UV. Dielectric properties, in particular space charge accumulation, are measured as a function of nanofiller content. Results indicate that space charge build up and charge mobility are affected largely by filler content. Concentrations of nanofiller of 5-7 wt% show a significant decrease of the space charge with respect to the base epoxy-resin and an increased mobility of negative carriers .
Characterization of a fiber-reinforced new fully aromatic liquid crystalline polymer
1998
A new rigid liquid crystalline polymer that demonstrates good mechanical and thermomechanical properties and acceptable processing temperature has been recently synthesized and characterized. The melting temperature and some thermomechanical properties do not seem, however, suitable for use in some applications at high temperature or in the presence of aggressive fluids. The use of appropriate inorganic fillers can overcome these shortcomings. In this work the new LCP, polymerized in a bench-scale apparatus, and the same sample filled with carbon fibers are characterized. The properties of the carbon fiber filled LCP are compared with those of another filled wholly aromatic commercial LCP,…
The effect of partial exfoliation of multilayer silicate filler particles on the elastic properties of a polymer composite
2018
Abstract A method for stepwise calculation the elastic constants of a three-phase composite, including the polymer matrix, the fully exfoliated silicate nanolayers and the platelike silicate particles in the form of multilayer intercalated stacks is considered. A theoretical analysis is carried out by using the Mori–Tanaka theory of an equivalent medium. The influence of degree of exfoliation (the ratio of exfoliated filler content to the total filler content) on the reinforcing efficiency is studied and discussed. A comparative analysis of experimental data of elastic modulus for a rigid polyurethane/montmorillonite composite and prediction results is carried out. It is shown, that with gr…
Triboelectrification of nanocomposites using identical polymer matrixes with different concentrations of nanoparticle fillers
2021
In this study, we investigate triboelectrification in polymer-based nanocomposites using identical polymer matrixes containing different concentrations of nanoparticles (NPs). The triboelectric surface charge density on polymer layers increased as the difference in nanoparticle filler concentration between the two triboelectric layers escalated, despite the fact that the polymer matrix was the same in both layers. This effect was observed in tests of various polymer types and filler NPs. Our mechanical experiments and finite element analysis simulations confirmed that polymeric triboelectrification is related to the surface viscoelastic deformation that occurs during mechanical contact and …