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A new molding technique is proposed to directly mold small parts from thermoplastic pellets. A small molding machine was designed and fabricated: the mold consisted of a transparent glass and a metallic frame; an infrared (IR) lamp provided the heat for the pellet melting. Molding tests were carried out by using three commercial thermoplastics and two metallic molds. Molding time and IR lamp power were changed to extract a moldability window for each combination of material and metallic mold. In the best process conditions, a high quality of the samples was obtained in terms of mold filling and surface aesthetics. POLYM. ENG. SCI., 50:2079-2084, 2010. [C]2010 Society of Plastics Engineers, INTRODUCTION The development of new processing systems is a fundamental effort for the scientific community which has to improve industrial efficiency. Nowadays, the main goals are the increase of the [...]

Thanks to its planar structure, graphene is characterized by unique properties, such as excellent chemical inactivity, high electrical and thermal conductivity, high optical transparency, extraordinary flexibility and high mechanical resistance, which make it suitable in a very wide range of applications. This paper details the state of the art in graphene coating applied to aluminum open-cells foams for the improvement of their mechanical and thermal behavior. Metallic foams are highly porous materials with extremely high convective heat transfer coefficients, thanks to their complex structure of three-dimensional open-cells. Graphene nanoplatelets have been used to improve thermal conductivity of aluminum foams, to make them better suitable during heat transfer in transient state. Also, an improvement of mechanical resistance has been observed. Before electrodeposition, all the samples have been subjected to sandblasting process, to eliminate the oxide layer on the surface, enabling a better adhesion of the coating. Different nanoparticles of graphene have been used. The experimental findings revealed a higher thermal conductivity for aluminum open cells foams electroplated with graphene. Considered the relatively low process costs and the improvements obtainable, these materials are very promising in many technological fields. The topics covered include surface modification, electrochemical plating, thermo-graphic analysis.

Plastic shaping was performed by means of the combination of IR heating and pellet softening in a semitransparent open mold. Three commercial thermoplastic materials were employed (acrylonitrile-butadiene-styrene, polyethylene, and polypropylene) and process curves were extracted depending on IR lamp power and interaction time. A simple exponential model was defined for the prediction of molded sample thickness and a master curve was built for all the materials. A scale factor was introduced depending on the IR lamp power and not on the material. Besides, the density of molded sample was monitored, obtaining in such conditions density values comparable to typical injection molded ones, even if a very low load was applied during pellet molding (10 N). POLYM. ENG. SCI., 46:896-903, 2006. © 2006 Society of Plastics Engineers, INTRODUCTION In recent years the wide application of plastics has led to the development of a lot of studies about polymer processing, to improve the product quality. In fact, it [...]

Abstract: In recent time, the quest for renewable materials for the development of packaging items is constantly increasing. The class of polylactic acids (PLAs) is the most promising one, although a broader scale commercial expansion of these polymers cannot leave unceasing enhancement of their functional properties aside, especially toughness and thermal stability. Similarly, continuous innovation in prototyping competitive easy‐route solutions for material processing is another key to successful industrial applications of PLAs. In this respect, this study deals with the design and formulation of innovative custom‐built PLAs for injection and compression molding, which are compostable, suitable for food contact, and characterized by a good compromise of mechanical properties and thermal resistance. Therefore, a commercial grade PLA was modified by reactive compounding extrusion with maleic anhydride (MAH)‐grafted PLA (PLA‐MA) and glycidyl methacrylate (GMA)‐grafted PLA (PLA‐GMA) and micro‐lamellar talc. Material structure and thermal response of the compounds were evaluated by differential scanning calorimetry (DSC) and Fourier transform‐infrared spectroscopy (FTIR). The experimental findings show that material structure and, especially, crystallization of the PLA can be controlled by fine‐tuning the compound formulation. In addition, achievement of the appropriate crystallization degree in the polymer can lead to compostable composite materials with good thermal stability. Accordingly, the custom‐built PLA formulations feature the potential to expand significantly the fields of application of compostable biopolymers, thus posing a valid alternative to both durable not compostable bioplastics and conventional plastics in injection and compression molding process. [ABSTRACT FROM AUTHOR]

This manuscript deals with to improve knowledge of the mechanisms of deposition of graphene on a flat surface. The analysis has been developed on a CPU cooler with experimental results and FEM analysis. The experiments are conducted by mounting the system over a heat source, while the force convection is facilitated by means of a blower. The transient temperature distribution in the CPU cooler is also observed. A model has been performed for modeling the thermal behavior of assembly structures with thin layers. The experimental observations are verified by simulation using a commercial FEM software. It was used a model of orthotropic thermal conductivity with variable values. The goal of the simulation has been to individuate the value of coefficient of thermal conductivity of the layer of graphene. The FEM results show how the graphene was deposited on the surface of CPU cooler and consequently, how this determine the coefficient of thermal conductivity. [ABSTRACT FROM PUBLISHER]

Magnesium alloys are widely employed in several industrial domains for their outstanding properties. They have a high strength-weight ratio, with a density that is lower than aluminum (33% less), and feature good thermal properties, dimensional stability, and damping characteristics. However, they are vulnerable to oxidation and erosion-corrosion phenomena when applied in harsh service conditions. To avoid the degradation of magnesium, several coating methods have been presented in the literature; however, all of them deal with drawbacks that limit their application in an industrial environment, such as environmental pollution, toxicity of the coating materials, and high cost of the necessary machinery. In this work, a plating of 2O3 film on a magnesium alloy realized by the fluidized bed (FB) technique and using alumina powder is proposed. The film growth obtained through this cold deposition process is analyzed, investigating the morphology as well as tribological and mechanical features and corrosion behavior of the plated samples. The resulting 2O3 coatings show consistent improvement of the tribological and anti-corrosive performance of the magnesium alloy. [ABSTRACT FROM AUTHOR]

The article presents a study regarding the use of tribological testing and scanning electronic microscope (SEM) to test in vitro and in vivo the wear performance of diamond-coated strips. The study performed tribological test was using a standard tribometer, in which the abrasive strips slid against stationary. The study showed that the diamond-coated strips presented a fenestrated structure characterized by diamond granules alternating with voids.