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ABSTRACT Polymer nanocomposites and their behavior have been widely investigated by several paths, including mechanical, rheological, and permeability tests, finding that several parameters (such as the polymer matrix, the nanofiller, their amounts, the presence of compatibilizers, processing parameters, etc.) can influence the main properties. However, less information is available regarding the creep response of polymer nanocomposites; in particular, few or no data are reported about the combined effect of different loads and different temperatures. In this article, the creep behavior of a low density polyethylene/organomodified clay nanocomposite has been investigated. The characterization of viscoelastic response has taken into account both the effects of applied load and temperature, which are often considered separately. Dynamic-mechanical and structural analysis was also performed in order to get a deeper understanding of the involved phenomena. The nanocomposite showed lower creep deformations (up to ∼20%) and the relative differences with the neat polymer matrix were found to be increasing upon increasing the applied load (up to ∼24%) and the temperature (up to ∼38%). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44180. [ABSTRACT FROM AUTHOR]

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 results show that compatibilization improves the mechanical properties in terms of elongation at break, as well as the rheological properties under nonisothermal elongational flow; furthermore, an unexpected effect has been found, since going from the isotropic to the anisotropic material, a fragile-ductile transition occurs, with a significant increase of the elongation values, while a small reduction of the elastic modulus was found, because of the lower crystallinity in comparison to isotropic samples. POLYM. COMPOS., 36:992-998, 2015. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have been attracting increasing interest for the fabrication of polymer-based nanocomposites because of their excellent properties. Traditional methods for the preparation of polymer/CNTs nanocomposites are in situ polymerization, solution blending, and melt mixing. The achievement of a good CNT dispersion and a percolation network is important in order to obtain better mechanical and electrical properties. However, the rheological behavior of polymer/CNTs systems, in particular regarding the extensional flow, has not been much investigated so far. In this work we present, for the first time, rheological data in non-isothermal extensional flow and an investigation on the effect of the extensional flow upon the final properties of several polymer/CNTs systems was carried out as well. Extensional flow led to higher mechanical properties and higher melt strength, but only a slightly reduced breaking stretching ratio. This result could be particularly interesting in the view of potential industrial applications such as film blowing and spinning. Morphological analyses also showed higher degrees of dispersion and variation in the CNTs final dimensions. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the processing, the influence of different processing techniques and the effect of the filler particle size on the properties of Mater-Bi/wood flour composites. It notes that polymer composites are known for their properties in terms of environmental impact, manufacturing cost and esthetic features. Results of the study showed an increase of the elastic modulus and viscosity caused by single-screw extrusion.

The article presents a study on the effects of antioxidants and processing temperature, time and speed on the competition between chain extension and branching formation in two high-density polyethylene samples with different molecular weight. It is said that the dependence of some of the properties of polymeric materials on the molecular structure and on the interactions among macromolecular chains makes those properties vulnerable to change when the polymer undergo modifications. The researchers observed that processing conditions, such as lower temperatures and higher molecular weight, would likely result to branching than chain scission.

The article discusses the mechanical properties of reused polyethylene ecocomposites stuffed with natural organic fillers. The use of natural organic fillers to boot postconsumer reused polymers is getting a growing interest. One of the main categories of polymer composites is corresponded through polymers filled with glass fibers which fit to a number of applications. Hence, the interest rose toward polymer composites stuffed with natural organic fillers with reused polymer matrices.

Background: Recent preclinical and clinical studies have shown that the [gamma]-aminobutyric acid-B agonist baclofen may be an effective treatment for reducing alcohol consumption. This preliminary open-label investigation examined the tolerability and effect of a 30-mg daily baclofen dose for reducing drinking, subclinical anxiety and depressive symptoms, and craving in alcohol-dependent subjects.Methods: Nine men and three women participated in a 12-week trial during which they took baclofen on a 10 mg thrice-daily regimen and received four sessions of motivational enhancement therapy. Each participant received a comprehensive physical and psychiatric screening before being enrolled. At each visit, side effects were monitored with a revised version of the Systematic Assessment of Treatment Emergent Events-General Inquiry, and drinking data were collected via the timeline follow-back interview. Participants also completed the Beck Depression Inventory, the Beck Anxiety Inventory, and the Penn Alcohol Craving Scale at each visit.Results: Baclofen was reasonably tolerated. Two participants discontinued because of side effects. No serious adverse events were noted. Six other individuals did not complete the trial. Overall, there were statistically significant reductions in the number of drinks per drinking day and the number of heavy-drinking days, and there was an increase in the number of abstinent days. Significant decreases in anxiety and craving were also shown.Conclusions: These findings suggest that baclofen is reasonably tolerated in an alcohol-dependent population, although the high dropout rate in the study is of concern. Baclofen may be effective for the reduction of drinking, anxiety, and craving for some alcohol-dependent individuals. A larger-scale placebo-controlled study is needed to further explore these effects and to determine the characteristics of those who respond to this medication. [ABSTRACT FROM AUTHOR]