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Molecularly imprinted biodegradable polymers are receiving considerable attention in drug delivery due to their ability of targeted recognition and biocompatibility. This study reports the synthesis of a novel fluorescence-active magnetic molecularly imprinted drug carrier (MIDC) using a glucose-based biodegradable cross-linking agent for the delivery of anticancer drug docetaxel. The magnetic molecularly imprinted polymer (MMIP) was characterized through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy, and vibrating sample magnetometry (VSM). The MMIP presented a magnetization value of 0.0059 emu g

This research aims to investigate the effects of the input parameters on the surface roughness as output parameters of CO2 laser and abrasive water jet (AWJ) machining technologies utilized in cutting sugar palm fiber reinforced unsaturated polyester (SPF-UPE) composite of three specimen thicknesses. The objective of this study is to collect data involve the optimal parameters of these technologies regarding the surface roughness response. The motive was to avoid defects arising use in the conventional cutting techniques. In the AWJ technique, stand-offdistance, traverse speed, and water pressure were chosen as variable input parameters to optimize the surface roughness, whereas laser power, traverse speed, and gas pressure were the variable input parameters in the CO2 laser cutting technique. Taguchi’s approach was used to estimate the input parameter’s levels that produce the best surface roughness. Analysis of variation (ANOVA) was used to determine the contribution of every single input processing parameter to the effect on the surface roughness response. Good surface roughness responses could be attained by applying the optimum input parameters determined in this study. The experimental results of the current research provide practical data for the cutting of SPF-UPE composites with CO2 laser and AWJ machining techniques, and the findings can be used as a good starting point for the testing of other similar composites under the same cutting conditions

Bio and Synthetic Based Polymer Composite Materials is a newly opened Special Issue of Polymers, which aims to publish original and review papers on new scientific and applied research and make contributions to the findings and understanding of the reinforcing effects of various bio and synthetic-based polymers on the performance of polymer composites [...]

The rapid use of petroleum resources coupled with increased awareness of global environmental problems associated with the use of petroleum-based plastics is a major driving force in the acceptance of natural fibers and biopolymers as green materials. Because of their environmentally friendly and sustainable nature, natural fibers and biopolymers have gained significant attention from scientists and industries. Cassava (

Current Progress in Biopolymer-Based Bionanocomposites and Hybrid Materials is a newly opened Special Issue of Polymers, which aims to publish original and review papers on the new scientific and applied research and make boundless contributions to the findings and understanding of the reinforcing effects of various synthetic and natural fibres on the performance of biopolymer composites [...]

Titanium alloys Ti-6Al-4V, have been broadly utilized in industries, particularly aerospace and medical manufacturing, owing to their good mechanical properties. In this work, high energy CO2 laser cutting of 3 mm-thick titanium alloys sheets is investigated with the aim of estimating the effects of the various laser cutting parameters such as, laser power (Pu), cutting speed (V) and of assist gas pressure (p), on the integrity of the cutting area. The objective of this study is to analyze the cut edge microstructure and to optimize the surface roughness using Taguchi method. Performances denote optimum cutting condition was obtained to be 3 kW for the laser intensity, 2400 mm/min for the cutting speed and 8 bars for gas pressure.

Recycling of materials attracts considerable attention around the world due to environmental and economic concerns. Recycled rubber is one of the most commonly used recyclable materials in a number of industries, including automotive and aeronautic because of their low weight and cost efficiency. In this research, devulcanized recycled rubber-based composites are designed with glass bubble microsphere, short glass fiber, aluminum chip and fine gamma alumina fiber (γ-Al2O3) reinforcements. After the determination of the reinforcements with matrix, bending strength and fracture characteristics of the composite are investigated by three-point bending (3PB) tests. Halpin–Tsai homogenization model is adapted to the rubber-based composites to estimate the moduli of the composites. Furthermore, the relevant toughening mechanisms for the most suitable reinforcements are analyzed and stress intensity factor, KIc and critical energy release rate, GIc in mode I are determined by 3PB test with single edge notch specimens. In addition, 3PB tests are simulated by finite element analysis and the results are compared with the experimental results. Microstructural and fracture surfaces analysis are carried out by means of scanning electron microscopy (SEM). Mechanical test results show that the reinforcement with glass bubbles, aluminum oxide ceramic fibers and aluminum chips generally increase the fracture toughness of the composites.

Ti-6242 is a super alloy which exhibits the best creep resistance among available titanium alloys and is widely used in the manufacture by WEDM of aircraft engine turbomachinery components. However, the final quality of wire EDMed surface is a great challenge as it is affected by various factors that need optimization for surface integrity and machine efficiency improvement. The aim of this study is to investigate the effect of a set of cutting process parameters such as pulse on time (Ton), servo voltage (U), feed rate (S) and flushing pressure (p) on surface roughness (SR) when machining Ti-6242 super alloy by WEDM process using a brass tool electrode and deionized water as a dielectric fluid. WEDM experiments were conducted, and SR (Ra) measurement was carried out using a 3D optical surface roughness-meter (3D–SurfaScan). As a tool to optimize cutting parameters for SR improvement, Taguchi's signal‐to‐noise ratio (S/N) approach was applied using L9 (3^4) orthogonal array and Lower-The-Better (LTB) criteria. Substantially, the findings from current investigation suggest the application of the values 0.9 µs, 100V, 29 mm/min, and 60 bar for Ton, U, S and p cutting parameters, respectively, for producing a good surface finish quality. Percent contributions of the machining parameters on SR (Ra) assessed based on ANOVA analysis are 62.94%, 20.84%, 11.46% and 4.74% for U, S, Ton and p, respectively. Subsequently, accurate predictive model for SR (Ra) is established based on response surface analysis (RSA). The contour plots for SR (Ra) indicate that when flushing pressure p converges to a critical value (80 bar), a poor-quality surface finish is highly expected with the excessive increase in U and S. Electron microscope scanning (SEM) observations have been performed on machined surface for a wide range of cutting parameters to characterize wire EDMed surface of Ti-6242. SEM micrographs indicate that the machined surface acquires a foamy structure and shows white layer and machining-induced damage that the characteristics are highly dependent on cutting parameters. At high servo-voltage, the decrease in pulse on time Ton and feed rate S results in a large decrease in overall machining-induced surface damage. Moreover, for high servo-voltage and feed rate levels, it has been observed that pulse on time could play a role of controlling the surface microcracks density. In fact, the use of a low pulse duration of cut combined with high servo-voltage and feed rate has been shown to inhibit surface microcracks formation giving the material surface a better resistance to cracking than at high pulse duration.

"Fibre-Reinforced Polymer Composites: Mechanical Properties and Applications" is a newly open Special Issue of Polymers, which aims to publish original and review papers on new scientific and applied research and make boundless contributions to the finding and understanding of the reinforcing effects of various synthetic and natural fibres on the performance of biopolymer composites [...]

Rubber recycling attracts considerable attention by a variety of industries around the world due to shrinking resources, increasing cost of raw materials, growing awareness of sustainable development, and environmental issues. Recycled rubber is commonly used in aeronautic, automotive, and transportation industries. In this study, recycled rubber composites designed with different reinforcements in the literature are scrutinized by means of toughening mechanisms, mechanical and physical properties, as well as microstructural and fracture surface analysis. Microscale reinforcements (glass bubbles, alumina fiber, etc.) and nanoscale reinforcements (nanosilica, graphene nanoplatelets, etc.) utilized as reinforcements in rubber composites are thoroughly reviewed. The general mechanical properties reported by previous studies, such as tensile, compressive, and flexural strength, are investigated with the main goal of optimizing the amount of reinforcement used. The majority of the studies on recycled rubber composites show that recycled rubber reinforced with microscale particles leads to the development of physical and mechanical properties of the structures and also provides low-cost and lightweight composites for several application areas. Moreover, recycled rubber containing composites can be suitable for applications where high toughness and high resistance to impact are desirable. The present review aims to demonstrate research on reinforced recycled rubber composites in the literature and prospective outcomes.

Additive Manufacturing of Polymer–Fiber Composites is a newly open Special Issue of Materials, which aims to publish original and review papers on new scientific and applied research, and make great contributions to the finding and understanding of the fabrication of fiber-reinforced polymer composites using current advanced additive manufacturing techniques [...]

International audience; In this research, the effect of processing input parameters on the kerf taper angle response of three various material thicknesses of sugar palm fiber reinforced unsaturated polyester composite was investigated as an output parameter from abrasive waterjet and laser beam cutting techniques. The main purpose of the study is to obtain data that includes the optimum input parameters in cutting the composite utilizing these two unconventional techniques to avoid some defects that arise when using traditional cutting methods for cutting the composites, and then make a comparison to determine which is the most appropriate technique regarding the kerf taper angle response that is desired to be reduced. In the laser beam cutting process, traverse speed, laser power, and assist gas pressure were selected as the variable input parameters to optimize the kerf taper angle. While the water pressure, traverse speed, and stand-off-distance were the input variable parameters in the case of waterjet cutting process, with fixing of all the other input parameters in both cutting techniques. The levels of the input parameters that provide the optimal response of the kerf taper angle were determined using Taguchi’s approach, and the significance of input parameters was determined by computing the max–min variance of the average of the signal to-noise ratio (S/N) for each parameter. The contribution of each input processing parameter to the effects on kerf taper angle was determined using analysis of variation (ANOVA). Compared with the results that were extrapolated in the previous studies, both processes achieved acceptable results in terms of the response of the kerf taper angle, noting that the average values produced from the laser cutting process are much lower than those resulting from the waterjet cutting process, which gives an advantage to the laser cutting technique.

The copper-aluminium (Cu-Al-Zn) based structures show shape memory behaviours that are low cost engineering applications, such as actuators, valves, etc., regarding to Ni-Ti-Al structures. These alloys have a useful transformation temperature that can be modified to lie between −100 and 100 °C. For a low cost production, a combined method through powder metallurgy processes (sinter-Forging) have been performed for the production the composite called “Zn-Cu-Al-1X” with addition of small amount of reinforcements. For two basic production methods, sintered-forging process have been carried out at the temperature of 550 °C and 650 °C with 1 h dwell time followed slow quenching and final cooling operation respectively. In the frame of the common research project, production of the scrap thin sheet copper based composites reinforced with pure nano aluminium (~5 wt %) and fine zinc particles were produced with addition of small amount of fine particles as secondary reinforcements. These composites will be used for the applications of the coupling and actuators in the aeronautical area. For mechanical basically for the tailored behaviour of this composite, three point bending (3 PB) and impact tests were performed. Microstructural analyses was carried out with Scanning Electron Microscopy (SEM). Ductility and tailored behaviour of this composite will be discussed through the toughness mechanism depending on the processing parameters.

Aluminium Metal Matrix Composites (AMMCs) have very light weight, high strength, and show better resistance to corrosion, oxidation, and wear. Impact resistance is an especially important property of these AMMCs which is essential for automotive applications. In this study, recycled aluminium matrix composites were designed through the powder metallurgy route. As matrix, fresh scrap aluminium chips (Alumix-123), by-product of machining coming from the French aeronautical company, were used. Fine -alumina particles (γ-Al2O3, 10 wt %), were used as main reinforcement element for the present work. As secondary reinforcements, Mo and Cu were added in the matrix. In this study, a typical low cost but high performance metal matrix composite was designed by using recycled aluminum chips (Alumix-123). This process comprises of the mixing, blending and compacting of aluminum chips through press moulding and pre-sintering and finally forging. In the final stage, material parameters were optimized for improving physical and mechanical properties of these composites. Further, the influence of reinforcement’s type and content on the mechanical properties has also been reviewed and discussed. Damping capacities and damage were analysed by drop weight and quasi static compression tests. Microstructures were analysed by the Scanning Electron Microscope (SEM).

Aluminum matrix syntactic foams (AMSF’s) may perform an important role on aerospace and automobile industry duo to its features like low density, good specific stiffness, vibration damping and high energy absorption efficiency. AlSiMg0.5Mn matrix syntactic foam was produced by thixoinfiltration of fly ash micro balloons. Expectometry, DSC and Thermo-Calc analysis were conducted prior the synthesis of the foam to comprehend the aluminum alloy thixoability. Compressive tests, SEM analysis and x-ray microtopography (Micro CT) were performed to investigate the compressive characteristics and failure mechanisms of the composite. The compressive tests showed an usual foam behavior with a plato and a compressive offset stress of 40.5 MPa. The Micro CT analysis confirmed a homogeneous densification resulting in a high energy absorption capacity.

In the frame of the common research project, the mechanical behaviour of recycled thin sheet Ti-Al based composites reinforced with scrap pure aluminium (AA1050) and boron, B reinforcement elements have been used with thin Ti-Al sheet recycled by hot forging method. The effects of chemical bonds during the production of these multifunctional sandwich composite structures were analyzed by 3-point bending tests to evaluated hyper elasticity behaviour. The same idea has been carried out this time on the Ti-Al based composites performed by sintered + forging through the powder metallurgy route by using different reinforcements such as TiB2, TiC, and B4C. Quasi static compression and low velocity impact (drop weight) tests have been performed on the sintered + forging specimens with a drop tower to observe the response of theses composites under the dynamic loading conditions. Interface and microstructure of these composites have been evaluated by Scanning Electron Microscope (SEM).

The present work, reviews the toughening mechanisms and microstructural analyses of recycled aluminium matrix composites reinforced with γ-alumina and pure recycled copper. This composite was manufactured by sintering and sinter + forging called the combined process. Static compression, 3-point bending, impact (drop-weight) tests were conducted to evaluate mechanical response of the composites. Additionally, wear and creep tests were carried out with a nanoindenter to evaluate wear and time dependent behaviour of this composite. Detailed analyses of microstructure of the composites was performed with Scanning Electron Microscopy (SEM) supported by EDS analyses. The results showed that, the composites have homogeneous structure without porosity and very homogeneous distribution of fine γ-alumina (Al2O3) and copper particles. Sinter + forging process yielded a material that had higher strength, hardness and better resistance to wear. This composite will be targeted for linkage applications where high toughness and high surface damage resistance is required.

Niobium is the best and excellent metal for many different industrial applications. Europe has not a Niobium reserve whereas Brazil has a major Niobium mining and produce %90 of the Niobium in the world as a raw material.

The present work, reviews the mechanical and microstructural analyses, of copper and silicon carbide reinforced recycled aluminium matrix (Alumix 431) composites manufactured by sinter+forging technique. Static compression, impact tests and also scratch damage tests were carried out. Detail analyses of Scanning Electron Microscopy (SEM) supported by XRD, thermal and electrical conductivity measurements have been carried out on the specimens before and after the tests.

In the frame of the common research project, manufacturing of thin sheet Ni-Ti based composites reinforced with Nb and TiB2 have been carried out through hot-forged bonding process for a high strength sandwich structure for the aeronautical engineering applications. Interface and bonding characteristics of hot forged composites have been evaluated heat treated at 550–600 °C depending on the operational parameters under laboratory conditions. Formability behaviour and delamination phenomenon have also been analysed by 3P Bending tests. An intermetallic phase layer has been carried out between the titanium and nickel sheet layers containing of hard particles reinforcements between the sheets by using hot forging process. Finally a high strength bonding has been carried out by mechanical joining and very strong chemical bonding diffusion during this process depending on the temperature and the time. With the finite element model developed with reference to these tests, the mechanical behaviour of the material is supported by simulations made with the Abaqus software. Finally, more detailed mechanical/physical properties of this developed material were investigated by applying wear and creep tests. Certain area in the microstructure have been analysed with SEM.

The objective of this work is to present analytical solutions for several 2D model problems to demonstrate the unique plastic fields generated by the implementation of micromorphic approach for gradient plasticity. The approach is presented for finite deformations and several macroscopic and nonstandard microscopic boundary conditions are applied to a gliding plate to illustrate the capability to predict the size effects and inhomogeneous plastic fields promoted by the gradient terms. The constitutive behavior of the material undergoing plastic deformation is analyzed for softening, hardening and perfect plastic response and corresponding solutions are provided. The analytical solutions are also shown to match with the numerical results obtained by implementing a user element subroutine (UEL) to the commercial finite element software Abaqus/Standard.

International audience; In this paper, the influence of processing input parameters on the heat-affected zone (HAZ) of three different material thicknesses of sugar palm fiber reinforced unsaturated polyester (SPF-UPE) composites cut with a CO2 laser was investigated. Laser power, traverse speed, and gas pressure were selected as the most influential input parameters on the HAZ to optimize the HAZ response with fixing all of the other input parameters. Taguchi’s method was used to determine the levels of parameters that give the best response to the HAZ. The significance of input parameters was also determined by calculating the max–min variance of the average of the signal-to-noise ratio (S/N) ratio for each parameter. Analysis of variation (ANOVA) was used to determine each input parameter’s contribution to the influence on HAZ depth. The general results show that the minimum levels of laser power and the highest levels of traverse speed and gas pressure gave the optimum response to the HAZ. Gas pressure had the most significant effect on the HAZ, with contribution decreases as the material thickness increased, followed by the traverse speed with contribution increases with the increase in material thickness. Laser power came third, with a minimal contribution to the effect on the HAZ, and it did not show a clear relationship with the change in material thickness. By applying the optimum parameters, the desired HAZ depth could be obtained at relatively low values.

International audience; Hybrid intermetallic composites (HICs-aluminum based matrix, new hybrid design) reinforced with titanium nitride (TiN) and alumina (c-Al 2 O 3) were designed and manufactured through the innovative combined method of sinter þ forging. This method results in highly dense materials with, in general, improved mechanical properties. In the composites TiN content was varied (10, 20 and 30 wt %) but c-Al 2 O 3 content was kept constant at 10 wt%. Additionally, 5 wt% each of Cu and Ni were mixed in to improve processing of the composites. The mechanical properties were specified by different destructive test methods (wear performance, micro hardness, quasi-static compression, three-point bending tests). Wear performance was investigated by scratch experiments. Scanning electron microscopy (SEM) was used to determine the microstructure, interface characteristics and the fracture surfaces. The SEM analysis yielded that TiN powders were located at the grain boundaries and this can be attributed to the improvement observed in the mechanical properties and wear performance with the addition of TiN.

Metal matrix composites are widely used in modern engineering as a result of the needing for distinct features into the same material, and for presenting such characteristics, the metallic foams have been increasingly used mainly from the mobility industry. Therefore a semisolid processing route for producing an AlSiMg0.5Mn matrix syntactic foam was idealized, by the thixoinfiltration of an industrial waste known as fly ash micro balloons. Preliminary a thorough study of the balloons morphology and chemical composition had been done, as also the AlMg2.5 thixoability through Spectrometry, Differential Scanning Calorimetry (DSC). The process parameters were defined to obtain a homogeneous pore distribution into the matrix and good wettability of balloons analyzed by x-ray micro tomography (Micro CT) and optical microscopy.