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The metal complexes and amine compounds are the most frequent categories of catalysts used in polyurethanes synthesis. Unfortunately, all auxiliary substances added to a synthesis increase the toxicological risk of final products used in a therapy. In the present study, polyether-urethane (PU) microstructures with and without catalyst were obtained. These structures were characterized by the measurement of samples’ pH, of their size and stability, were obtained and the skin irritation potential. The results show that samples with a neutral pH, PU microstructures with sizes between 120 and 165 nm and with a medium stability. It was found that the microstructures from syntheses with catalyst present increased values of skin irritation.

Water is an important element of life, while every industry in its processes uses an important amount of water. Following processes, the water is contaminated and requires water treatment technologies. Unconventional methods to wastewater treatment, in the last years, use membrane technology as one of the most reliable processes for contaminants removal. In this article, the influence of the different concentrations of polysulfone (PSf) on the polymeric membranes properties was studied. These membranes were obtained through phase inversion method and with different polymer concentrations: 23, 25, 27 and 30 wt.%. The performance of the membranes was studied by pure water flux, permeability and retention. It has been observed that by increasing the polymer concentration, the pure water flux and the permeability will decrease. Retention was determined using methylene blue, which is one of the most utilized dye from industry and it could be observed that by increasing the polymer concentration the retention degree of the pollutant also increases. In order to explain the evolution of membrane permeability at different polymer concentrations, surface hydrophilicity by contact angle method and cross-section SEM imaging were used.

Since the time of their introduction into medical practice, biomesh were criticized for their lack of tissue integration and the rejection due to the organism reaction for an element that is not autologous. The mechanisms by which these changes of contact between the tissue and the foreign material were produced were initially incompletely understood, but over time the involvement of the immune system mediated by the cellular or humoral local inflammatory reaction was established.

Graphene oxide and graphite filled polyester composites were prepared by using conventional melt-mixing methods in order to improve tribological performance of polyester. It was investigated friction stability, microhardness, friction coefficient, and specific wear rate of the composites in details. It was found that the presence of graphite and graphene oxide influenced friction coefficient and wear rate of the composites. Graphene oxide decreased wear rate with increasing of test speed and graphite decreased wear rate for composite for all speeds. Tribological performance of the polyester/graphene composites is mainly attributed to bigger thermal conductivity for graphene, which can easily dissipate the heat which appears during the friction process at bigger forces. The positive influence of graphite on coefficient of friction (COF) of the composites is the result of the clivage of graphite layers during the loadings due to van der Waals weak bonds between the graphite layers.

Materials based on acrylic resins are commonly used in dental practice. These are obtained through various technologies, which determine the chemical, physical and biological properties of the final product, which can influence the inflammatory processes in the periodontal tissue. To evaluate the effects of these materials, we identified the concentrations of TGFb1 and IL8 in crevicular fluid in 23 patients with temporary dentures made of polymethyl methacrylate by two polymerization methods: (1) a product processed immediately prior to application, wherein the polymerization of the material occurs in the oral cavity; and (2) a product processed in the dental laboratory from a prepolymerized block (block-type PMMA), and applied directly into the patient’s mouth. The results of our study revealed a significant correlation between the IL-8 inflammation marker and the clinical parameters in the periodontal tissue exposed to the polymerization of the material in the oral cavity.

This paper presents the development and characterization of polymer composites based on natural rubber, crosslinked using two types of vulcanization systems, as follows: the classical method using sulfur and curing accelerators and the method using peroxide in the presence of a polyfunctional monomer - trimethylolpropanetrimethacrylate. The composites were made with 0 parts to 100 parts rubber (phr) and 40 phr filler content. The physical-mechanical characteristics of resulting composites depend on the crosslinking method and on the composition. The mechanical parameters of materials were derived by processing the transmissibility curves, derived for samples with known dimensions and density. The main vibration frequencies and the quality factor, derived in the vicinity of resonances, allow to derive the elasticity and internal damping of materials.

The main aim of this study was to prepare and characterize polymeric nanoparticles containing two cardiovascular active pharmaceutical ingredients: valsartan (VAL) and amlodipine besylate (AML). Six formulations were evaluated with different ratios of AML:VAL:PLGA (1:16:17, 1:16:34, and 1:16:51) and different stirring speed (1200 and 2400 rpm). Encapsulation efficiency (EE, %) and particle size analyses were performed to characterize and optimize the formulation. All loaded nanoparticles showed a high EE (%), nano-size, negative x-potential and a high homogeneity.

Utilization of computer-aided design/computer-aided manufacturing (CAD/CAM) rapidly increases in dental medicine. Making of computer-engineered complete denture is based on scanning of patient data, designing of prosthesis and milling or rapid prototyping. This is digital denture, term that includes innovative devices, software programmes and corresponding materials. Industrially polymerized cross-linked polymethyl methacrylate (PMMA) is the material used for fabrication of digital denture. The aim of this study is to analyze the different cross-linked PMMA used for fabrication of CAD/CAM complete denture.

The study aimed to assess the changes of the surface roughness induced by some acidic beverages on indirect restorative materials by using profilometry. Twenty samples of three composite resins (Ceramage, SR Adoro, Luna-Wing) and three ceramics (IPS In Line, Hera Ceram, Reflex Dimension) immersed in three acidic beverages (Red Bul, wine, Coca Cola), for 5 minutes, three times daily, 14 days. The control samples were immersed in artificial saliva during the study periode. After the end of the erosive cycles and before to determine the surface roughness of the samples in the study groups, all the samples were immersed in artificial saliva for 18 hours. The surface roughness was determined in relation to the baseline surface using profilometer Perthometer_M1 (Mahr Gottingen GmbH, Germany). The immersion of the indirect restorative materials tested in the three acidic beverages lead has resulted to changes in their surface roughness. The most aggressive was wine, followed by Coca Cola, and Red Bull.

This paper presents the results of the experimental researches obtained in the three-point test of the glass-fiber-reinforced polymeric composites. Mathematical modeling of experimental results was performed using a virtual instrument (VI) developed in the graphical programming language called LabVIEW. In order to process the experimental data and display the results, the virtual instrument (VI) allows both the reading of experimental data from a saved text file from the same folder as the current VI file and the direct entry of experimental values into a control element disposed on its front panel. The virtual instrument described in this article is part of a more complex project used for the mathematical modeling of the experimental data obtained in determining the physic-mechanical characteristics of glass fiber randomly reinforced polymeric composites.