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The search for green composite for sound-absorbing material has increased a significant interest. In this study, polystyrene (PS) composite foam filled with primary sludge and boiler ash from pulp mill was produced. The product was characterized using analytical techniques such as FTIR, XRD, SEM, TGA, and DSC, while the mechanical properties and sound-absorbing coefficient were analyzed regarding ASTM D 2240 and ASTM E-1050-98, respectively. The results showed that the sludge has 1β crystalline polymorph cellulose from the pulp. The chemical reaction can be seen by the chemical bond formed during the mixing process. The peak expansion occurred at 1600.44 cm-1 indicating the presence of a C=C functional group of maleic anhydride with polymer and filler. SEM images showed that the filler was distributed and dispersed into the polymer matrix and no agglomeration was produced. The sound-absorbing composites had complied ISO 11654:1997 regarding the sound absorption coefficient rating level on materials for rooms with sound absorption classes D and C with the value of α 0.328-0.793.

This study was geared to analyze the preparation methods of pullulan acetate-based nanoparticles loaded with 5-fluorouracil, as well as the potential of pullulan as a biopolymer matrix for obtaining nanoparticles applied in the delivery of anticancer drugs (5-FU). Various methods were used to produce pullulan acetate-based nanoparticles loaded with 5-FU, including nanoprecipitation, modified nanoprecipitation, and double emulsion. Pullulan was previously chemically modified with acetic anhydride, dimethylformamide and pyridine, and yielded pullulan acetate. Pullulan was made using the Aureobasidium pullulans strain through a fermentation procedure. UV-Vis Spectro-photometric and dynamic light scattering (DLS) methods were used to assess entrapment effectiveness, size, and polydispersity index (PDI) of pullulan acetate-based nanoparticles loaded with 5-FU. Based on the properties of the nanoparticles obtained, the optimum preparation method was chosen. The maximum entrapment efficiency was found in pullulan acetate nanoparticles loaded with 5-FU generated by a double emulsion method. The mean hydrodynamic size and PDI of all nanoparticles were adequate. The best formulation showed faster 5-FU release profile in acid phosphate-buffered saline (pH 5) than in phosphate-buffered saline pH 7.4. According to the findings, pullulan derivatives have a great potential for producing nanoparticles that might be used to deliver anticancer medicines.

Intended to draw a frame of the impact of plastics usage and the role of the circular economy, this paper relied on specific literature, data from different studies, case studies, reports and databases existing on the research area. Being produced at low costs and used in a wide range of fields, plastics has been confirmed as one of the most impactful inventions for human. Recently, during the pandemic years, plastics has gotten multiple usages, such as keeping a hygienic sanitary environment facing the critical situations, with a highly increased role in the fight against the SARS-COVID-19 crisis. It is also well known that plastics presents risks arising from its production flow, linked to a huge degree of massive pollution with high impact on the environment. Plastic waste exposed to the environment generated problems and it is of huge concern for all forms of life. As plastics products are present all around the world, there is an increasing statement to one-use plastics in the environment. Thus, it is urge to take actions for managing this situation as appropriate, to protect the environment and reduce the consumption of plastics, which can be achieved by developing and sustain the circular economy, as a new research field to explore. Through this paper we intended to emphasize the importance that, both theoretical contribution and practical measures, have on the production, the use and recycling of plastics and on the circular economy.

The recycling and high-valued added reuse of automotive plastics have elicited global attention as the number of end-of-life vehicles increase. In the paper, the two-stage high-voltage electrostatic separation is used to explore the sorting of passenger vehicle plastic mixtures of PP, ABS and PVC. The purities of PP, ABS and PVC are all higher than 97%, and the recovery rates are 55%, 93%, and 48%, respectively. Taking PP plastic as an example, the mechanical properties of the recycled materials and the different ratios of recycled and new material mixtures are studied. Results show that the passenger car bumpers reproduced with a 7:3 ratio of new and recycled materials can satisfy the performance requirements. The finding provides a reference for the high additional value reuse of other automotive plastics.

Purpose was to determine the viscoelastic properties of three root canal sealers as a function of temperature, time and frequency using dynamic oscillatory measurements. Methods: Measurements were performed on the dynamic oscillatory rheometer set to temperatures: 25°C, 35°C, 40°C and 65°C. Stress sweep and frequency sweep tests were used in order to determine storage moduli G’, loss moduli G’’ and complex viscosity η*. Results Higher values of storage compared to loss moduli indicate the more pronounced solid-like behavior of tested materials. EndoREZ showed the highest values of G’ and G’’ moduli at all temperatures. With temperature increase the G’ and G’’ moduli of Sealapex and EndoREZ increased while the moduli of AH Plus decreased. With frequency increase all materials showed viscosity decrease exhibiting non-Newtonion, shear-thinning behavior. With temperature increase AH Plus demonstrated viscosity decrease, while the viscosity of Sealapex and EndoREZ increased. Clinical significance: All tested materials were temperature, time and frequency dependent and this dependency varied between them. The obtained results may be used to predict the rheological behavior of root canal sealers in different temperature conditions, thus helping as to estimate optimal handling characteristics for specific clinical applications.

Atherosclerosis can affect the blood vessels in any region of the body and the stenosis (narrowing) can be located on an artery that vascularize important organs, such as the brain, abdominal organs or limbs. The endovascular surgery is a modern approach to vascular pathology through minimally invasive techniques (puncture, minimally vascular approach) and it represents an enrichment of the arsenal of surgical techniques and brings considerable improvements in post-operative and long-term outcomes The use of polymer drug-coating balloons is an attractive alternative because they can offer the promise of an improved patency compared to the simple balloons and a reduction in the need for stents. The aims of this study were to describe the polymer materials and to compare the medical endpoints obtained in angiosome-targeted infrapopliteal angioplasty using a simple balloon with two layers, based on polyethylene, and respectively a drug-coated balloon that contains a multiblock copolymer from polyethylene, poly(cylohexylethylene), polyisoprene and poly(1,3-butadiene) covered by Paclitaxel. The balloons were characterized by differential scanning calorimetry, stress-strain and puncture tests in order to describe their physical and mechanical characteristics. On the other hand, 51 patients with critical limb ischemia were treated with different balloon angioplasty and they were monitored for 12 months after the intervention; the following parameters have been evaluated: diabetes, hypertension, renal insufficiency, hemodialysis, stroke, dyslipidemia, heart disease, heart failure, body mass index, number of angiosomes, creatinine, and wound healing, leg salvage and amputation-free survival at 1, 2, 3, 6, 9, 12 months. Significant associations were found in the case of anterior-tibial-artery and posterior-tibial-artery angioplasy and the age, hypertension and renal insufficiency. On the other hand, the results indicate that the drug deposition on the surface of the balloons lead to improved values for the observed medical endpoints. In conclusion, this study reveals that angiosome-based infrapopliteal angioplasty with drug-coated balloons can be associated with better wound healing and leg salvage.

The goal of this research is to show that epoxy resin (ER) / coir fiber mats (CFM) hybrid composite laminates with nano-silica particle (NP) reinforcement improve mechanical characteristics and water absorption. Lately, it has been employed in automotive, aerospace, and structural industries where coir fiber-reinforced polymers are safe for ecologically friendly composite applications. The Compression - Hand layup technique is used to make the epoxy composites reinforced with natural coir fibres and nano-silica particles in various weight fractions (5, 10, 15, 20 and 25% by weight). Mechanical parameters such as tensile, flexural, compressive, impact strength, thermal conductivity and also water absorption of composites are evaluated in this study. Scanning electron microscopy is also used to analyze the surface morphology of cracked surfaces (SEM). Hybrid nanosilica-coir fiber mat reinforced epoxy resin has decreased water absorption (percent) suggesting better mechanical qualities. Furthermore, the hybrid epoxy-containing 20% nano-silica coir mat improves all the said mechanical properties.

The study aims to investigate the influence of TiO2 nanoparticles on the permeation and retention properties of polymeric membranes used in wastewater nanofiltration systems from the medical sector. The research is focused on the influence of the TiO2 nanoparticles concentration on the membrane properties. Additives in general determine enhanced membrane properties like permeation and retention capacity. Hydrophobicityhowever, is decreasing due to the nanoparticles affinity for water and this have an important effect on the permeation properties, at the same time with the decrease in surface roughness, with an important influence on the fouling effect. Membranes with four different concentrations of TiO2 nanoparticles were studied, from 0 to 2% nanoparticles. Results showed that small percent of nanoparticles have an important impact on the permeation properties of the membranes, finding that at 2% nanoparticles the permeation decreases due to the nanoparticles aggregations which are blocking the pores.

Despite important progress in the field of the thin flexible transistor (TFT)-based electronics, a major challenge still exist for organic TFTs to decrease the operating voltage, which is related to the properties of the dielectric and semiconductor layers from the OTFTs structure. In this paper, we present the electrical behavior of two biocompatible polymers, polyvinylpyrrolidone (PVP 360) and polyvinyl alcohol (PVA), regarding the application as insulating layer in thin-film transistors. The PVA and PVP 360 thin films were deposited onto epoxy resin copper double-sided layer and polyethylene tere-phthalate/Indium tin oxide (PET/ITO) substrates by sol-gel method, spin-coating technique. Two sol concentrations (1 and 5 wt. %) were prepared and the contact angle onto the used substrates was measured using a digital microscope camera. The obtained films have been characterized by scanning electron microscopy (SEM) and dielectrical behaviour. For electrical measurements, the metal-insulating-metal (MIM) structure was realized by cooper electrodes deposition at room temperature, onto the top of thin films, by magnetron sputtering method. The current (I) - applied voltage (from -5 to +5 V) curves were measured in air at room temperature (RT), using the Picoammeter homemade device. PVA and PVP 360 thin films showed low leakage currents with values within ± 2 nA for ±5 V range.

The aim of this work is to study the possibility of using the products of aminolytic destruction of polyethylene terephthalate (PET) and their derivatives in polymer composite materials with vibration-absorbing properties, which provide effective damping of vibrations of technogenic and natural origin in a wide temperature and frequency range. The paper considers a modern method of recycling PET waste with a mixture of amino alcohols - monoethanolamine and triethanolamine, taken in two different ratios. As a result of the destruction reaction, terephthalic acid diamide (N, N`-bis (2-hydroxyethyl) terephthalamide) is formed. To accelerate the destruction process, microwave radiation of various powers of 200, 540 and 700 watts was used. The optimal conditions for aminolytic decomposition of PET were determined: the time and power of microwave radiation with PET conversion up to 95% and the yield of the target product (terephthalic acid diamide) 80-85%. The destruction process was carried out according to a closed cycle of using reagents, without the use of catalysts and at atmospheric pressure, which to a certain extent reduces the energy consumption and increases the environmental friendliness of this method of PET decomposition. The aminolytic degradation product of PET (terephthalic acid diamide) was used as a monomer in the polycondensation reaction to obtain a new oligomer (terephthalic acid oligoesteramide). The degree of polymerisation (n) is in this case 7 to 11 (number of chain links). The obtained oligomer and the PET degradation product were investigated as new components in elastomeric compositions based on chloroprene rubber and in compositions based on thermoplastic elastomers. It has been demonstrated that the introduction of an oligomer based on a PET degradation product reduces the viscosity of elastomeric compositions by 25-35%. The study was supported by a grant from the Russian Science Foundation No. 21-79-00301, https://rscf.ru/project/21-79-00301/.