Influence of Matrix Polarity on the Properties of Ethylene Vinyl Acetate–Carbon Nanofiller Nanocomposites

A series of ethylene vinyl acetate (EVA) nanocomposites using four kinds of EVA with 40, 50, 60, and 70 wt% vinyl acetate (VA) contents and three different carbon-based nanofillers—expanded graphite (EG), multi-walled carbon nanotube (MWCNT), and carbon nanofiber (CNF) have been prepared via solution blending. The influence of the matrix polarity and the nature of nanofillers on the morphology and properties of EVA nanocomposites have been investigated. It is observed that the sample with lowest vinyl acetate content exhibits highest mechanical properties. However, the enhancement in mechanical properties with the incorporation of various nanofillers is the highest for EVA with high VA content. This trend has been followed in both dynamic mechanical properties and thermal conductivity of the nanocomposites. EVA copolymer undergoes a transition from partial to complete amorphousness between 40 and 50 wt% VA content, and this changes the dispersion of the nanofillers. The high VA-containing polymers show more affinity toward fillers due to the large free volume available and allow easy dispersion of nanofillers in the amorphous rubbery phase, as confirmed from the morphological studies. The thermal stability of the nanocomposites is also influenced by the type of nanofiller

Poly(ethylene-co-vinyl acetate)/clay nanocomposites: Effect of clay nature and organic modifiers on morphology, mechanical and thermal properties

Nanocomposites based on an ethylene vinyl acetate copolymer (27 wt% vinyl acetate) and various (organo-modified) clays have been prepared by melt blending and their morphology, tensile and thermal degradation properties have been evaluated. Special attention has been paid to the influence of the clay nature and origin (montmorillonite or fluoromica) as well as on the nature of the ammonium cation organic modifier. It has been shown that nanostructure and tensile properties mainly depend on the nature of the organic modifier while the delay in thermal volatilisation of EVA during thermo-oxidation is mainly driven by the nature of the clay (mainly its aspect ratio), with no significant influence of the nanostructure of the nature of the organic modifier. (c) 2005 Elsevier Ltd. All rights reserved

Hémorragies sous anticoagulants oraux en gériatrie : résultats d’une étude observationnelle.

Over recent years, new oral anticoagulant agents (NOAC) have been commercialized as a new treatment in order to prevent or treat thromboembolic events. Although the use of NOACs is easier than for vitamin K antagonists (VKA), their risk-benefit balance still raises concerns, especially in the elderly. To evaluate bleeding complications with anticoagulants agents (NOAC and VKA) among a geriatric population. A retrospective study performed in the four units of the acute geriatric department of CHU Charleroi (116 beds). All the patients who received at least one dose of oral anticoagulant (NOAC or VKA) during their hospitalization between January 1st2013 and May 31th 2014 were enrolled. Medical files of 242 patients were analyzed, and the type and severity of bleeding were recorded. Mean age was 84 ± 5.4 years old. Seventy-three percent were prescribed VKA. Rivaroxaban was the most prescribed NOAC among this population. Atrial fibrillation was the primary indication of oral anticoagulation in 73% with VKA and 94% with NOAC. Fourty-six patients presented a bleeding (38 patients (22% of patients with VKA) with VKA and 8 patients with NOAC (12% of patients with NOAC)). We found 13 major bleedings with VKA and only one with NOAC. The results of this study are encouraging concerning the utilization of NOACs in the geriatric population. However, larger studies are needed to confirm this.info:eu-repo/semantics/publishe

Polymer/carbon nanotube nanocomposites: Influence of carbon nanotubes on EVA photodegradation

International audienceThe influence of carbon nanotubes on the photodegradation of EVA/carbon nanotube nanocomposites was studied by irradiation under photooxidative conditions (at λ > 300 nm, at 60 °C and in the presence of oxygen). The influence of the nanotubes on both the photooxidation mechanism of EVA and the rates of oxidation of the matrix was characterized on the basis of infrared analysis. On one hand, it was shown that the carbon nanotubes act as inner filters and antioxidants, which contribute to reduction in the rate of photooxidation of the polymeric matrix. On the other hand, it was shown that light absorption could provoke an increase in the local temperature and then induce the photooxidation of the polymer. The competition between these three effects determines the global rate of photooxidation of the polymeric matrix. Several factors are involved, the concentration of the carbon nanotubes, the morphology of the nanotubes and the functionalization of the nanotube surface

Internal structure and linear viscoelastic properties of EVA/asphalt nanocomposites

The effect of the addition of two different organoclays as a third component in polymer modified asphalts has been investigated. Ternary mixtures were prepared by adding clay and poly(ethylene-co-vinylacetate) to the asphalt, either separately, or in the form of a premixed master batch. The performed characterizations allowed the determination of how the two methods of mixing influence the interactions between asphalt and polymer and therefore the final rheological properties. In particular, it was shown that the clay had a compatibilizing effect on asphalt and polymer and that a high compatibility between clay and polymer led to a better dispersion of the polymer in the asphalt, thus influencing the final rheological properties of the studied systems