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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.

Plastic materials based on biopolymers are of great importance in biomedical field. In this article, chitosan was investigated to elucidate the impact of the surface topography parameters and wettability on its interaction ability with certain biological molecules. The physicochemical properties of chitosan in acetic acid environment are analyzed by molecular modeling to predict some of the films properties. Morphology images show a hill–valley-structured surface of nanoscale level, with low surface bearing properties and valley fluid retention. Wetting features were determined for evaluation of the balance between the adhesion and cohesion forces acting at the biointerface. wetting or dewetting behavior of chitosan with several biological media.

This work was aimed at synthesizing the N, N`-isophthalic bis(piperonylic acid) dihydrazide (PAID) to be as a new crystallization accelerator for poly(L-lactide) (PLLA), and a detailed investigations of the non-isothermal crystallization, melting behavior, thermal decomposition behavior and mechanical properties of PLLA nucleated by PAID were performed applying differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and electronic tensile tester. The melt-crystallization proved that the PAID could act as a heterogeneous nucleating agent to significantly promote the crystallization in cooling, even the crystallization was still able to be accelerated upon the fast cooling at 50 oC/min. The final melt temperature was another crucial factor for PLLA’s melt crystallization, and when the final melt temperature was 170 oC, the onset crystallization temperature and melt-crystallization enthalpy was almost up to 150 oC and 56.8 J/g upon cooling of 1 oC/min, respectively. Furthermore, the chemical nucleation was proposed to be the nucleation mechanism of PAID for PLLA via the preliminary theoretical calculation. For the cold-crystallization, the addition of PAID exhibited an inhibition for the crystallization of PLLA, but the total crystallization process depended on the heating rate and PAID concentration. The single melting peak after cooling of 1 oC/min indicated that the crystallization had been thoroughly completed in cooling. Additionally, the single melting peak with different locations after full crystallization resulted from the different crystallization temperatures. A comparison in the onset decomposition temperature implied that the presence of PAID only slightly decreased the thermal stability of PLLA. The mechanical testing showed that, in contrast with the elongation at break, the existence of PAID enhanced the tensile strength of PLLA.

The article presents the influence of accelerated UV ageing on the structural properties of selected polymer materials. In this study, 3 types of materials from a group of thermoplastics known as PP30T, PE, POM were used. The test samples were prepared by injection moulding. In turn, an accelerated UV ageing process (600 h) was carried out in the UV Test chamber with fluorescent lamps characterized by a wavelength of 313 nm. Changes in the structure of the tested materials were observed by using an optical microscope. Measurements of gloss on the surface of primary samples that were exposed to UV rays were also taken. In addition, the structure of primary and aged samples was tested by differential scanning calorimetry (DSC). The conducted studies have demonstrated the impact of UV radiation on the changes in the surface layer of tested materials.