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Since the commercialization of Li-ion batteries by Sony in 1990, the performance of cathode materials used in Li-ion batteries has improved significantly. However, Li-ion batteries cannot respond to the needs of the energy storage market in terms of energy density. In order to increase theoretical energy density of active materials, molar mass of the active material should be decreased, or electron number participating per reaction or reaction potential should be increased. In this study, it was aimed to produce cathode materials for Li-ion batteries in the form of composite nanofibers via electrospinning method. For this purpose, porous LiFexMn1-xPO4/C composite nanofibers (1 > x > 0) were synthesized with a scalable, two-step method (electrospinning and subsequent heat treatment). The morphological, structural and electrochemical properties of the LiFexMn1-xPO4/C composite nanofibers were determined by scanning electron microscope, X-ray diffraction and galvanostatic charge/discharge tests. Cathodes made of LiFexMn1-xPO4/C composite nanofibers showed various advantages such as long cycle life, improved electrochemical performance etc. due to the presence of carbon and LiFexMn1-xPO4 in the composite structure. With the addition of Mn to the structure of LiFePO4/C composite nanofibers, electrochemical performance was improved. LiFe0.8Mn0.2PO4/C composite nanofibers showed the best performance in terms of energy density among the samples. Further increment in Mn/Fe ratio resulted declining electrochemical capacity and energy density.

The thermoset polymers and the thermoplastic polymers matrix composites require different forming techniques due to the different properties of two classes of polymers. While the forming technique for thermoset polymer matrix composites does not require the use of special equipment, the thermoplastic polymer matrix composites imposes the rigorous control of temperature and pressure values. Each type of polymer transfers to the composite a set of properties that may be required for a certain application. It is difficult to design a composite with commonly brittle thermoset polymer matrix showing properties of a viscoelastic thermoplastic polymer matrix composite. One solution may consist in mixing a thermoset and a thermoplastic polymer getting a polymer blend that can be used as matrix to form a composite. This study is about using PMMA solutions to obtain thermoset-thermoplastic blends and to mechanically characterize the obtained materials. Three well known organic solvents were used to obtain the PMMA solutions, based on a previous study concerning with the effect of solvents presence into the epoxy structure.

A significant part of the research and production activities is represented in the field of bioengineering by the biomaterials used in hard tissue restorations. They are of great interest in dental science, intending to improve technological aspects, monitoring their biological responses to the living organisms, but also to redesign economic aspects, beginning with the choice of raw materials. In the present work, light-curing composite biomaterials were made from a composite polymer matrix consisting of specific concentrations of bisphenol A-glycidyl methacrylate base monomer (Bis-GMA), a mixture of two co-monomers, triethylene glycol dimethacrylate and ethoxylated bisphenol A-dimethacrylate (TEGDMA/BisEMA), and two alumina nanopowder concentrations (5 wt.% and 10 wt.%). These materials were mechanically tested for flexural strength and compressive strength. The structural analysis of these materials consisted of SEM microscopy and EDX elementary mapping. In order to extract 3D projections of sample surfaces, but also to produce indicative values of their roughness, the SEM micrographs were processed with open-source software. In order to observe a clear evolution of the mentioned properties, the composite biomaterials were compared with materials formed only with the Bis-GMA/TEGDMA/BisEMA composite, and with a commercial composite resin, Filtek™ Supreme Ultra Universal Restorative, also. The findings showed an increase in the mechanical properties of the materials manufactured concerning the concentration of nanoparticles of aluminum. EDX analyzes confirmed the good homogeneity of nanoparticles in the polymer matrix. Mechanical properties of the manufactured nanocomposite biomaterials were reported 28.8 % higher than the control biomaterial. The comparison results with the commercial resin composite are encouraging.

Theobromine (Th) was documented during the last decades for its important role in the prevention of dental caries, having this role dueto its antibacterial action against the Streptococcus mutants and S. sanguinis, thus reducing the formation of dental biofilm on the teeth surface. Thermally induced interactions of theobromine in 1:1 mass ration bynary mixture with different types of Poly(methyl methacrylate) based materials and the induced interactions between Poly(methyl metha-crylate) based materials and HA were performed using thermal analysis and FTIR spectroscopy. This study aims to be a preliminary study for various mixtures of HA/methacrylate-based materials and Th with usage in dental applications. The instrumental techniques used can be successfully applied in the characterization of dental materials and can lead to conclusions on how to use them.Studies have led to the conclusion that Th can be used for the treatment of early decay by incorporation into the polymer material. It is recommended to use these materials as successive layers (Th with HA and after that dental material).

By the extrusion and injection technique, polymer-based composite samples (polypropylene and thermoplastic polyurethane) were obtained with BaTiO3 filler in concentrations between 0 and 35 %. Following the preliminary characterizations performed by coupled thermal analysis techniques, it was found that the composite samples obtained have thermal stability up to a temperature of about 250 oC and can be processed by extrusion at temperatures between 180 and 240oC. Above this temperature, a series of degradation processes take place by successive thermooxidation with the formation of volatile products.The electrical characterization of the composite samples was performed by the dielectric spectroscopy technique, which showed that the Ätgä dielectric losses increase as the BaTiO3 content of the composite increases. The maximum increase being recorded at 50 Hz (the slope Ätgä /% BaTiO3 about 0.003 /% BaTiO3). It was also found, that the electrical conductivity (ó) of the composite increases with the increase of content in BaTiO3 so that ó at 100 kHz for the composite with 35 % BaTiO3 is about 50 times higher than for the reference sample M 0 (without filler).

The present paper reported the obtaining of an environmental friendly adsorbent based on sodium alginate, chitosan and glass bubbles. CaCl2 was used as crosslinking agent for sodium alginate favoring the interactions by physical bonds between the negative groups (-COO) of biopolymer and the Ca ions. The experimental study to determine the Cu(II) uptake using an atomic absorption spectrometer was conducted in the testing stand at the 1:50 and 1:100 ratios between the adsorbent mass and the amount of pollutant in solution. The number of cycles of regeneration of the adsorbent material was also evaluated. The characterization of alginate/chitosan/glass bubbles adsorbent by scanning electron microscopy (SEM) coupled with energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR) showed that the Cu(II) was found out on the surface of adsorbent.

Knowing how to deform the Turcite thermoplastic material under the action of conical penetrators is a means of obtaining information on the processing of the counterpart (made from a metal material with higher hardness) with which it comes into contact.The paper aims to theoretically determine the depth of penetration of the thermoplastic material under the action of some conical penetrators and to establish the coefficient of static and kinetic friction under the action of these penetrators. The proposed model will be validated experimentally on a tribological stand made for this purpose.

The effect of Crosslink density on Cut and Chip resistance was affected on a typical 100 percent styrene-butadiene rubber (SBR)-based tire tread compound. In order to successfully develop products for tires used in off-road or poor roads and other demanding rubber applications, it is important to understand the C&C effect in rubber. Crosslink density varied by varying the sulphur to the accelerator ratio and also by changing the process aids. Basic polymer, filler and other ingredients such as activators and anti-degradants have remained unchanged. In the first setup, the sulphur was kept constant and the accelerator varied and the reverse was done in the second setup. It was made to achieve different crosslink density by changing the oil dosage and adding different resins. An attempt has been made to correlate Cut and Chip resistance to other physical properties. All these tests have been identified and optimized by the traditional tire tread compound.

The chemical composition of a hybrid resin made of natural Dammar resin and epoxy resin (along with the related hardener), in proportion of volume of 60 and 40%, respectively, was studied based on EDS analysis. The results of the study are presented in this paper. The presence of epoxy resin was necessary to generate a rapid polymerization process. The material details of the hybrid resin were investigated using SEM. A high-resolution image of a hybrid resin sample was obtained. The weight loss of the hybrid resin at certain temperature values using thermo gravimetric analysis was measured. In addition, the surface roughness of the hybrid resin was characterized using two methods. By the first method, the classical one, the roughness was measured using two profile parameters and five analysis lines, namely the functional dependence between the roughness height and the gray level of the analyzed surface image. By the second method, the average roughness method, the surface texture of a hybrid resin specimen was measured and the roughness profile was obtained as the difference between the primary profile and the middle line of the filter determined with the Gaussian profile filter. Finally, several possible areas of use of this type of resin have been proposed based on the properties obtained.

In this work, biodegradable Poly(L-lactide) (PLLA) was modified through adding a new organic additive N, N`-bis(benzoyl) 1, 4-naphthalenedicarboxylic acid dihydrazide (NABH). A comparison on crystallization of the pure PLLA and PLLA/NABH revealed that the NABH as effective heterogeneous nucleation sites enhanced PLLA𠏋 crystallization, and an increase of NABH loading was able to further accelerate crystallization rate of PLLA; whereas a faster cooling rate was not conducive to PLLA𠏋 crystallization, but the appearance of obvious crystallization peak upon cooling at 30ºC/min confirmed the advanced enhancing role of NABH for PLLA crystallization again. The investigation on influence of the final melting temperature on the crystallization behavior of PLLA showed that the 170 ºC was optimum final melting temperature for enhancing crystallization, even the onset crystallization temperature of PLLA/NABH were higher than 150ºC. The melting processes of PLLA/NABH after different crystallization not only could reflect the previous crystallization, but also depended on crystallization temperature and heating rate. Thermal decomposition results showed that the existence of NABH slightly weakened thermal stability of PLLA, and the maximum difference in onset thermal decomposition temperature was only 9.4ºC comparing with the pure PLLA. However, the presence of NABH in PLLA matrix seriously weakened optical property.