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Despite the advantages of the non-flammable, good performance and low price, poly (vinyl chloride) (PVC) still suffer from poor thermal stability, restricting its melting process and applications. Although addition of some heat stabilizers can be used to improve the low thermal stability, so far, they normally compromise the environmental issues and smoke density of PVC during combustion. In this work, a series of La doping Mg-Al layered double hydroxides (LaLDHs) with different molar ratio of La3+ / Al3+ were successfully synthesized by coprecipitation-hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), Scanning Electron Microscopy (SEM) and Transmission electron microscopy (TEM). The results showed that the as-prepared LaLDHs exhibit plate-like morphology with a lateral size around 100-180 nm. The different as-prepared LaLDHs were introduced into PVC as heat stabilizer to prepare PVC nanocomposites. The thermal stability and smoke suppression of PVC nanocomposites were investigated by TGA, thermal aging, Congo red and smoke density rating test (SDR), respectively. All the results demonstrated that PVC-LaLDHs2 nanocomposites containing 2% LaLDHs2 (the molar ratio of La3+ / Al3+ is 1 / 3) were optimized, which achieved the maximal T50% value of 337.2 oC, minimal SDR value of 45.6%, and prolonged the thermal aging time from less than 10mins to 90mins, respectively thermal stability time from 1242s to 2751s. In addition, the tensile strength and elastic modulus of PVC-LaLDHs2 respectively increased by 84.4% (56.6 MPa) and 75.5% (1019.4 MPa) with little affecting elongation at break of PVC. LDHs (layered double hydroxides); rare earth ions; thermal stability; smoke suppression; poly (vinyl chloride)

Hybrid composites of in-situ microfibrillar recycled polyethylene terephthalate (rPET)/glass fiber (GF)/polypropylene (PP) were developed as an economical and environmentally friendly alternative to glass fiber reinforced thermoplastic PP composites. The effect of replacing glass fibers with in-situ formed polymer microfibrils on mechanical and viscoelastic properties of the composites was investigated with tensile, flexural, and dynamic mechanical tests. Characterization results showed that mechanical and viscoelastic performance of 34% glass fiber reinforced PP can be obtained with 24% glass fiber, 10% microfibrillar rPET composites. Compatibilization effect of the maleic anhydride grafted PP (MA-g-PP) was studied using Fourier transform infrared (FTIR) spectroscopy. The scanning electron microscopy (SEM) images confirmed the formation of the rPET microfibrils in the hybrid matrix. Besides, composites with MA-g-PP compatibilizers showed significantly improved fiber-matrix interfacial adhesion on the SEM images.

The study performed the biomechanical testing of polymethylmethacrylate (PMMA) specimens with unreinforced progressive antibiotic loading, compared to samples reinforced with Kirschner wires, by subjecting these specimens to mechanical compression forces. A difference was observed in the yield of the reinforced specimens with Kirschner wires, in which an antibiotic concentration that exceeded the usual amount was used. In this antibiotic combination of vancomycin powder and liquid gentamicin, the spacer seemed to have a superior structure compared to using only the antibiotic in liquid form. These results are superior to the usually loaded specimens (not exceeding the threshold of 4 g of antibiotic per 40 g of cement), the maximum force recorded being of 20.98 kN and the minimum of 11.54 kN. The reinforced specimens indicated higher values of force, registering differences that varied between 10 kN and approximately 19 kN, thus considering that through the reinforcement with Kirschner wires, the biomechanical qualities of the cement spacers considerably improved.

The study is highlighting the possibility of modeling the properties of composite materials based on recycled polypropylene (PPR), flour feathers(FF), and compatibilizers (C). The composite materials with 10% and 20% feather flour content were mixed and processed with a two-stage extruder having four heating zones between 200-230°C, in order to obtain granules. The granules were injected in various forms to evaluate the properties. The composite materials have been evaluated for determination of melt flow index (1900C; 2.16kg), density, Charpy impact, breaking strength, elongation at break, and the dielectric behavior. The results showed that the introduction of feather flour in the polymer matrix based on PPR leads to decreased flow properties as well as physical and mechanical properties. The solution in solving these deficiencies was to use compatibility agents, that would improve these properties. The physico mechanical properties were analyzed in order to identify a composite with optimal properties for industrial application.

The goal of the research is to develop an experimental mathematical model of pan coating process effect on the biodegradable polymer and to determine optimal process parameters. The polymer solution was conducted with phosphated di-starch phosphate, polyvinyl alcohol, and polyacrylic acid and performed as material coating for the controlled-release urea fertilizer. The image analysis method has been used to determine the particle size distribution, Sauter mean diameter of the particle and layer thickness that is novel. The central composite rotatable design has been selected to determine the regression models of the process, which described the relationship between two objective variables as layer thickness, release time with angle of pan, spray flow, and coating time. The statistical analysis results indicate the fitness of model.

The Additive Manufacturing (AM) industry has expanded steadily, occupying the market very quickly. New types of 3D printers have appeared and new types of polymeric and composite materials have been developed for these printers. Thus it passed very quickly from the stage in which the parts that were made by rapid prototyping (RP) only to be exposed (demonstration parts) to stage AM the parts are fully functional. Of course, the future of AM is still on the horizon, it is barely visible. The other technologies for forming the geometry of the part, ie subtractive manufacturing technology and formative manufacturing technology are still the basis of industrial production. Each technology has its own advantages and disadvantages and is chosen on a case-by-case basis, depending on the objectives pursued. In this paper, a study is made on the rapid prototyping of a single pump rotor part. The material of the piece is of polymer type, ABS. The piece was made in two variants: by additive manufacturing technology (PolyJet) and by subtractive manufacturing technology (milling). After processing, several parameters were followed, such as the functionality of the part, the surface quality, the mechanical tensile strength, the dimensional accuracy, and last but not least the manufacturing cost and the duration of the manufacturing cycle. The data thus obtained were processed with an artificial intelligence program for decision making.

The materials used in additive techniques are initially in a plastic state so that they can be inserted into various cavities or easily molded after which they pass into a rigid phase. This process is performed by various methods, depending on the nature of the material. The study aims at analyzing the chemical and biological behavior of flexible acrylates compared to classical acrylates, whose structure was optimized through the introduction, at a structural level, of certain polymeric and antiseptic structures in view of obtaining a high degree of biocompatibility, the elements of variability consisting in the difference between the two polymerization regimes, the polymerization under pressure and the classical polymerization.The polymerization of acrylic resins by the technique of thermobaro-polymerization with injection compensation leads to the formation of materials with superior impact resistance. The pressure regime is very important, being a factor that influences the polymerization without being initiated. Breaking strength is an essential element in assessing the quality and duration of the prosthesis use.

The acrylic resins are the materials most frequently used for dentures realization, which allow to obtain resistant prosthetic constructions with a suitable aesthetic appearance. Depending on the polymerization mechanism, these resins are classified in self-curing, heat-curing or light-curing materials. In order to obtain a properly cured resin with a good mechanical strength, it is necessary to know the properties of the material, the correct dosage of the components and the strict observance of the curing regime. This article aims to evaluate the mechanical parameters of two main categories of resins frequently used in dental practice for removable dentures realization - heat-curing and self-curing resins. For this purpose, the tensile strength and the fracture strength, the Young`s modulus values, the surface roughness were analyzed comparatively. The results demonstrate that, after processing and finishing, both types of resins have similar structures and no significant differences regarding the mechanical behavior are registered.

In this paper, the problem of the behaviour of soft jaws that can be used to replace the steel jaws of grippers is studied. One of the advantages of additive manufacturing is the printing of fully functional parts. Choice of material is often related to the part strength. The mechanical properties of 3D printed parts should meet the service loading and, also, must be comparable with parts produced by traditional manufacturing techniques - machined parts or injection moulding. From the specialized literature information regarding the test results for effect of various printing parameters on part strength are available made in laboratory conditions and for standard test sample. For ABS materials various values for Young module are presented varying from 1.5 GPa to 2.15 GPa, for 100% infill rate and various modified parameters such as raster orientation. In order to study the behaviour of soft gripper jaws several part were printing and the resistance to bending was tested, by simulating the way a gripper works. An experimental stand was built using a force transducer and a displacement transducer to measure the deformation of the jaw, obtained by 3D printing, under load. The mechanical elastic hysteresis loop during an experimental loading/unloading was plotted and the amount of mechanical energy lost during a cycle, dissipated because the internal friction, was determined. Finite element analysis method was applied to make a comparison with the experimental results. In the finite element analysis, several simulations were considered, varying Young`s modulus for the tested material.

Lercanidipine has found to be effective in lowering blood pressure among the potent calcium channel blockers, through its action on L- type calcium channels. However, the major disadvantage associated with Lercanidipine is, it is a BCS class II drug having low solubility bioavailability is around 10% through oral route due of extensive first pass metabolism. The present study is aimed to prepare and evaluate polymeric nanoparticles of Lercanidipine using a combination of two bottom down techniques, High speed homogenizer and Probe sonication. Preformulation studies like, DSC, FTIR using surfactants such as Tween 80, Sodium Lauryl sulphate, Polyvinyl Alcohol, singely and in combination were used. A full factorial method was utilized to study the effect of various factors such as surfactant concentration, homogenization speed, sonication amplitude and sonication time on Lercanidipine nanoparticles in two levels. Optimized nanoparticles (with PVA as surfactant) showed an average particle size of 141 nm, PDI 0.248 and zeta potential +6.46. Formulation was further optimized using Design Expert 10 software. Optimized formulation was found to be stable during 3 months stability studies as per ICH guidelines.