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The search for nanofillers in polymer industries to improve composite material properties for several purposes has increased significant interest. In this study, dioctyl phthalate-plasticized polyvinyl chloride (PVC) reinforced either with sepiolite or MgO was produced in which the characteristic of composite sepiolite/MgO-filled was compared. Sepiolite and MgO were added into PVC matrices with 5, 10, and 20 phr concentrations. The product was characterized using analytical techniques such as SEM, TGA, DSC, and the mechanical properties regarding ASTM D 638 Type IV. The tensile strength of the composite increased with the presence of sepiolite and MgO. The highest result showed at the concentration of 5 phr. However, the elongation at the break of the composite decreased with the addition of MgO. The morphology analysis showed that PVC-filled sepiolite had a rough surface with a sharp fracture, but no sharp fracture was found in the PVC-filled MgO. At a concentration of 5 phr, both sepiolite and MgO increased the thermal properties of PVC with a residue of PVC control, PVC-Sepiolite, and PVC-MgO at 14.74%, 19.34%, and 26.33% respectively.

Plastic parts in retired passenger vehicles are derived from non-renewable oil resources, and recycling them can conserve energy and reduce the burden on the environment. Effective separation is the premise of recycling vehicle plastics, and electrostatic separation is a clean and efficient method of plastic separation. On the basis of a self-developed, two-stage electrostatic separation equipment, this study investigated the high-voltage electrostatic separation of polyamide (PA), polyethylene (PE), and polypropylene (PP) mixtures. First, the single-factor experiment method was used to explore the influence of voltage, electrode spacing, and electrode inclination angle on the separation results. Second, the response surface methodology was employed to comprehensively analyze the effects of voltage, electrode spacing, and electrode inclination angle on the recovery rates of the three particles and their interactions. The optimum parameters for the secondary electrostatic separation of the three particles were determined to be 44 kV voltage, 156 mm electrode spacing, and 10° electrode inclination. Experimental verification showed that after the two-stage, electrostatic separation device was optimized through the response surface methodology, the purity of the PA particles reached 98.56%, and the recovery rate reached 96%. The purity of the PP particles reached 81.93%, and the recovery rate was 87.5%. Meanwhile, the purity of the PE particles reached 86.11%, and the recovery rate was 73%. This research provides a reference for the multi-stage, high-voltage, electrostatic separation of various automotive plastic particles.

Chitosan is a natural biopolymer, being a cationic polysaccharide, which is generally obtained by deacetylation of chitin. Aminophosphorylated chitosan is of interest due to the presence of its multiple functional groups of aminophosphonate type that can serve as chelating sites and their interesting biological and chemical properties. This paper presents the achievement of antibacterial adsorbent based on modified chitosan with aminphosphonic groups and Zn(II) ions. The new aminophosphonic adsorbent supported on chitosan was modified by impregnation with Zn(II) ions using the hydrothermal reaction. It was prepared from the natural biopolymer of chitosan type. The obtained product was characterized by different techniques: FTIR, SEM / EDX, XPS and thermogravimetric analysis. This research aimed to test modified chitosan against the strains (Staphylococcus aureus and Pseudomonas aeruginosa). In order to highlight the effect of the presence of Zn(II) ions, both the chitosan functionalized with aminophosphonic groups and impregnated with Zn(II) ions (code: ChitPZn) and the chitosan functionalized with aminophosphonic groups (code: ChitP) were tested. It was found that Zn(II) ions impregnation on chitosan functionalized with aminophosphonic groups increases the antibacterial effect in both St. aureus as well as at Ps. aeruginosa.

Polyurethanes are widely used in different industries, as insulators, coating or adhesive agents. Several of their medical applications include various implants, artificial heart valves, surgical instruments or catheters. The versatility and biocompatibility of these polymer products lead to their application as drug or genetic material delivery systems. We aim to evaluate different parameters that affect the encapsulation efficiency of polyurethanes, using a computational approach, in order to improve the transmembrane transfer and the bioavailability of an active agent loaded inside a drug delivery system. 2D structures of different etheric- and esteric-PU macromolecular chains were modeled in ChemBioDraw, while molecular structures of the three active agents (Deoxyribonucleic acid, Guanidine,1`-[(methylethanediylidene)dinitrilo]di-, mixt. with Calf Thymus DNA, and 2`-Deoxycytidine-5`-phosphonic acid) were imported from PubChem database. Open software such as Open Babel and PyRx were used to convert files and to analyze the binding affinity based on the predicted dissociation constants. Structural parameters of the tested compounds were calculated in HyperChem 8.0. The polymer chains showed very large values for van der Waals potentials, refractivity and polarizability compared to the active agents. Even if there were no major differences in terms of binding affinities between the tested assemblies, the best orientation ligand-macromolecule was the 2`-Deoxycytidine-5`-phosphonic acid encapsulated inside LDI and PEG-based polyurethane carrier. On the other hand, the values of Root Mean Square Deviation have identified that the best geometric fit to be the Deoxyribonucleic acid encapsulated inside IPDI and PCL-based polyurethane macromolecule. The assemblies between genetic materials and polyurethane drug delivery systems are not experimentally known and this study could orientate towards new potential therapies. These results indicate that there is no significant change in the values of the docking parameters with different PU synthesis precursors; however, a good compatibility between LDI and PEG-based chain and 2`-Deoxycytidine-5`-phosphonic acid was identified. Further studies are needed to evaluate the in vitro and in vivo utility of this finding.

This paper presents preliminary results and discussion on two aramid fabrics in order to establish their stab resistance when used as panels with different numbers of layers. Twaron fabrics SRM509 and CT736CMP, were arranged in 16 and 20 layers and in a combination of them (10 layers SRM509 and 10 layers CT736CMP). Samples of 130 mm x 130 mm were cut from the fabrics, weighed and measured for thickness. All tests were done for an impact energy of 24 J (the resulting impact velocity being 3 m/s). The blade had the geometry recommended in the standard Stab Resistance of Personal Body Armor NIJ Standard–0115.00 as P1. The conclusion of this analysis is that the better behavior to stab is obtained for panels that have higher gradients in time, for all four characteristics here discussed: force, displacement, absorbed energy and velocity. When using hybrid panels, the results could intermediate those of the components, this solution could be recommended for reasons as price, weight.

The torus or toroidal surfaces are geometries that can be easily found in various industrial applications, from containers, devices, cartwheels, design objects and even machine parts, being also a geometric primitive often used in solid constructive geometry. For a better understanding of the torus–type surface mechanical behavior, this paper aims to study the toroidal geometry manufactured from ABS material by using the FDM 3D printing method and subjecting each sample to compression tests to identify the influence of the sample filling percentage in the case of triangular pattern.

In this study, Ethylene-vinyl acetate (EVA) based composites filament, with four different volume fraction of the nano-sized carbon black particles (NCB) were produced by melt mixing using a single extruder. The morphology of the EVA/NCB was studied using SEM, where a 3-D network of the NCB was presented. Thermal gravity analysis (TGA) measurement was utilized, denoting the degradation temperature of EVA, and presetting the actual volume fraction of NCB in the composites. Mechanical properties, e.g. elongation at break, tensile strength of the EVA/NCB filament was studied. Most importantly, the strain sensoring behavior of the EVA/NCB was investigated ultilizing a tensile testing machine coupled with a pico-ammeter. The gauge factor for various strain range, as well as the relative change of the resistance during the cyclic measurement of the NCB/EVA composites was calculated. Moreover, the measured data were fitted using some mathematical modellings, which reveals the potential of the strain sensoring behavior of the NCB/EVA composites in this study. Overall, this study introduces a durable NCB/EVA composites using as strain sensor oriented to industrial large-scale production, and the proposed modelling provides an effective evaluation method on its strain sensoring behavior.

In this study, a selective flexible flow path system was developed so that two types (4 cavities) of different shapes, sizes, and weights could be produced simultaneously or individually according for a production plan.The selective flexible flow path system is a method of exchanging sprue parts manufactured in a branched or one-way direction. This method reduces mold costs and provides production flexibility because only the desired cavities can be filled with resin in a multi-cavity mold. Since parts with different shapes and weights are produced simultaneously or separately, it is most important to maintain a uniform filling balance between each cavity. To optimize of filling balance, the optimum value of control factors was derived using the Taguchi technique (DOE) to improve the filling balance. In addition, molds were manufactured under the optimal conditions after checking the filling balance through a CAE analysis. As a result, the flow balance ratio of each product was confirmed to be within 0.6%, and the precision of the product was guaranteed to be within 1%. In this study, it was confirmed once again that the improvement of the filling balance of the family mold had a great influence on the production.

The paper generalizes the Timoshenko model for thick bars, using a new model that is applied to the vibration study of multilayer composite bars. In the proposed mathematical model, three coefficients are introduced that take into account the non-uniformities of the tangential and normal stresses in the bar section. The vibrations of some composite bars with a polypropylene honeycomb core with a thickness of 10 mm, 15 mm and 20 mm are experimentally studied, on the faces of which one or two layers of carbon fiber, respectively glass fiber was poured. For each analysed bar, the stiffness and the equivalent modulus of elasticity are determined and the variation of the damping coefficient according to the length of the bar is studied.

The paper presents the results obtained after the tribology of composite materials with organic components intended for the manufacturing of brake shoes for motor and towed rolling stock. We analyzed the tribological behaviour of the samples of experimental composite material in comparison to the phosphorous cast iron frequently used for manufacturing brake shoes.