Artículos de revistas: "Organic polymeric additives"

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Morlens, S., N. Romà, S. Ricart, A. Pomar, T. Puig y X. Obradors. "Thickness control of solution deposited YBCO superconducting films by use of organic polymeric additives". Journal of Materials Research 22, n.º 8 (agosto de 2007): 2330–38. http://dx.doi.org/10.1557/jmr.2007.0296.

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We show that the thickness of yttrium–barium–copper–oxide (YBCO) superconducting films grown from trifluoroacetate precursors can be strongly modified using polymeric additives, while deposition conditions by spin or dip coating remain unchanged. A screening of different families of organic additives has been performed, and the best results have been achieved using polymers having an oxygen functionalized backbone. Two different polymeric additives, polyvinyl pyrrolidone (PVP) and poly(ethylene glycol) (PEG), have been more thoroughly investigated, and thermal analysis suggests that PEG is the most promising alternative because the pyrolysis step of the new complex precursors remains sharp and narrow and hence the final homogeneity of the film is preserved. The combination of anhydrous trifluoroacetic acid (TFA) solutions and poly(ethylene-glycol) (PEG8000) as additive can produce an increase of the YBCO film thickness up to 300%, while keeping a fast pyrolysis process and high critical current densities.

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Mastalygina, E. E., L. A. Kolesnikova y S. D. Brovina. "Antimicrobial Additives for the Creation of Functional Polymer Materials for Various Applications". Occupational Safety in Industry, n.º 8 (agosto de 2023): 7–14. http://dx.doi.org/10.24000/0409-2961-2023-8-7-14.

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Creation of the functionalized polymeric materials with additional properties is an important area of research. In this review the prospects are discussed related to imparting antimicrobial properties to polymers for further use of materials in the field of medicine, packaging products, hygiene and agricultural products, and other branches of industry. Based on the results of the assessment of existing methods, it is shown that the most technically simple approach is the introduction of an antimicrobial additive into the bulk of the polymer during its processing, which allows to avoid additional processing steps for the finished products. However, this approach is inexpedient from the point of view of saving the additive, which, as a rule, performs its functions only on the surface of the polymer products. Surface treatment of the finished polymer products with antimicrobial agents (coatings) is most preferable from the point of view of saving expensive additives. Among the antimicrobial additives used, inorganic substances (metals and their compounds), as well as organic and organometallic substances, including antibiotics, can be distinguished. As a rule, additives of natural origin, which are a mixture of substances, are distinguished into a separate group. According to the conducted analysis of the antimicrobial additives used, it is established that the inorganic antimicrobial additives are the most versatile for modifying various polymers. They can be used in the form of nanosized particles, which virtually eliminates their effect on the performance properties of the polymeric materials. In addition, the additives of inorganic nature have a high chemical and thermal stability, and therefore are suitable for introducing into the polymer melt at the stage of its processing. Organic and organometallic substances are, as a rule, more sensitive to high temperatures, which limits their use as additives in the polymeric materials. However, they are more effective against pathogenic microorganisms.

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Koukoumtzis, Vasilis, Georgia C. Lainioti, George A. Voyiatzis y Joannis K. Kallitsis. "Novel Hybrid Organic–Inorganic Polymeric Coatings Containing Phosphonium or Acidic Groups for Improving Flame Retardancy of Wood". Coatings 13, n.º 4 (9 de abril de 2023): 754. http://dx.doi.org/10.3390/coatings13040754.

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Flame-retardant polymeric coatings with high limiting oxygen index (LOI) were prepared by combining inorganic mineral huntite (H5) and polymeric additives synthesized in the present work into a polymeric formulation. In order to improve the dispersion of the Mg- (and Ca)-based H5 particles, additives containing phosphonium and acidic groups were employed to homogenize the inorganic fillers into the polymer matrix. Specific blend combinations of the commercial matrix Ecrovin® LV 340 eco with huntite and the additives poly(benzyltriphenylphosphonium-co-4-styrene sulfonic acid) P(SSH-co-SSBTPB60) and poly(hexadecyltributylphosphonium-co-4-styrene sulfonic acid) P(SSH-co-SSTBHDPB80), combining acidic and phosphonium groups, led to LOI values of 34.5% and 33.5%, respectively. The novel flame-retardant polymeric coatings inhibited the combustion of the coated wood substrates, which is attributed to the combination of acidic groups that promote the dispersion of inorganic filler in the polymer matrix and phosphonium groups that support the increase in LOI values.

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Rosen-Kligvasser, Jasmine, Adi Pariente, Maayan Shaked, Ran Y. Suckeveriene, Roza Tchoudakov y Moshe Narkis. "Extended Additives’ Performance in Polyethylene Thin Films". MRS Advances 1, n.º 53 (2016): 3601–6. http://dx.doi.org/10.1557/adv.2016.494.

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ABSTRACTFor several decades additives have been incorporated into polymeric systems to improve desirable properties, and eliminate undesirable properties. When added to a polyethylene film, the additives migrate to the films’ surface and their concentration decreases; over time the additive’s effect desists. To solve this problem, efficient methods for extended performance are being sought. Extended additives’ performance is necessary to avoid frequent substitution of polyethylene films for different applications (e.g. greenhouses plastic coverings); as a result, reducing plastic waste and contributing to environmental sustainability. Over the course of our work, a new method of additives’ controlled migration has been developed, by grafting the additive molecules to nano-particles (NPs) via a radical reaction. The particles were used as physical migration retarders. Nano-particles were chosen due to their small size, which does not scatter light significantly. It was thus possible to make composites that retain their optical clarity. Furthermore, the small size of the particles leads to a large interfacial area for grafting. This work focuses on additives such as antifogs (AF) and UV protecting agents. The NPs serve as physical migration retarders, as well as UV protecting agents; the organic grafted molecules serve as AF additives. The existence of the grafted AF molecules to the NP’s surfaces was confirmed; the polyethylene containing AF grafted particles (LLDPE/AF-NPs) has shown satisfactory and promising AF and UV protection performance.

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Abd El-Wahab, H. "Synthesis and characterisation of the flame retardant properties and corrosion resistance of Schiff’s base compounds incorporated into organic coating". Pigment and Resin Technology 44, n.º 2 (2 de marzo de 2015): 101–8. http://dx.doi.org/10.1108/prt-05-2014-0042.

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Purpose – This paper aims to report on the synthesis and characterisation of new flame retardants and anticorrosive additives based on Schiff’s base compounds, which were added physically to organic coating. Design/methodology/approach – Flame retardants are incorporated into polymeric materials either as additives or as reactive materials. Additive-type flame retardants are widely used by incorporating into polymeric materials by physical means. In this research, Schiff’s base (azomethine) compounds are added physically to alkyd paint as flame-retardant additives. Elemental analysis, infrared spectroscopy and proton nuclear magnetic resonance spectroscopy were used to characterise the structure of the prepared Schiff’s base compounds. Thermal gravimetric analysis was used to evaluate their thermal stability. Experimental coatings were manufactured on a laboratory scale, and then applied by brush on wood and steel panels. Findings – Results of an oxygen index value indicated that alkyd paints containing Schiff’s base compounds as additives exhibit very good flame-retardant effects. Also the physical, mechanical and corrosion resistance properties were studied to evaluate the drawbacks of the additives. The additives did not affect the flexibility of the paint formula. The gloss and the impact strength were decreased by the additives, but the hardness, adhesion and corrosion resistance were significantly improved by these additives. Research limitations/implications – Alkyd resins are the most extensively used synthetic polymers in the coating industry. Nitrogen compounds are a small but rapidly growing group of flame retardants which are in the focus of public interest concerning environment-friendly flame retardants. So, the focus of this study is on Schiff’s base compounds as flame retardants and anticorrosive additives for alkyd resins to assess their applicability. Practical implications – Schiff’s base compounds can be used as new additives in paint formulations to improve the flame-retardant and corrosion properties. Originality/value – In recent years, there has been considerable interest in the nitrogen-based family of materials because they not only have a wide range of thermal and chemical stabilities, but can also provide improved thermal and flame-retardant properties to polymers. The present paper reports on the synthesis and characterisation of Schiff’s base compounds and their performance in alkyd resin coatings.

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Lozinsky, Vladimir, Olga Kolosova, Dmitrii Michurov, Alexander Dubovik, Viktor Vasil’ev y Valerij Grinberg. "Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO". Gels 4, n.º 4 (8 de octubre de 2018): 81. http://dx.doi.org/10.3390/gels4040081.

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Urea (URE) and guanidine hydrochloride (GHC) possessing strong chaotropic properties in aqueous media were added to DMSO solutions of poly(vinyl alcohol) (PVA) to be gelled via freeze–thaw processing. Unexpectedly, it turned out that in the case of the PVA cryotropic gel formation in DMSO medium, the URE and GHC additives caused the opposite effects to those observed in water, i.e., the formation of the PVA cryogels (PVACGs) was strengthened rather than inhibited. Our studies of this phenomenon showed that such “kosmotropic-like” effects were more pronounced for the PVACGs that were formed in DMSO in the presence of URE additives, with the effects being concentration-dependent. The additives also caused significant changes in the macroporous morphology of the cryogels; the commonly observed trend was a decrease in the structural regularity of the additive-containing samples compared to the additive-free gel sample. The viscosity measurements revealed consistent changes in the intrinsic viscosity, Huggins constant, and the excess activation heat of the viscosity caused by the additives. The results obtained evidently point to the urea-induced decrease in the solvation ability of DMSO with respect to PVA. As a result, this effect can be the key factor that is responsible for strengthening the structure formation upon the freeze–thaw gelation of this polymer in DMSO additionally containing additives such as urea, which is capable of competing with PVA for the solvent.

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Oluwunmi, Paul A., Aaron R. Finney y P. Mark Rodger. "Molecular dynamics screening for new kinetic inhibitors of methane hydrate". Canadian Journal of Chemistry 93, n.º 9 (septiembre de 2015): 1043–49. http://dx.doi.org/10.1139/cjc-2015-0003.

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The development of polymeric and oligomeric chemical additives that can control the nucleation and growth of gas hydrates remains a topic of major research interest, with important implications for energy security and the environment. In this paper we present a molecular dynamics study of eight different oligomeric compounds that have been proposed as potential kinetic inhibitors for methane hydrate. The results show that statistically significant variations in hydrate formation, induced by the chemical additive, can be observed within a relatively modest series of molecular dynamics simulations, thus opening the way for computational screening for optimal additives to control hydrate formation. One amino acid oligomer, asparagine, was found to be more active than a number of synthetic inhibitors, including PVCap.

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Faccini, Mirko, Lorenzo Bautista, Laura Soldi, Ana M. Escobar, Manuela Altavilla, Martí Calvet, Anna Domènech y Eva Domínguez. "Environmentally Friendly Anticorrosive Polymeric Coatings". Applied Sciences 11, n.º 8 (12 de abril de 2021): 3446. http://dx.doi.org/10.3390/app11083446.

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This paper provides a synthetic and comprehensive overview on environmentally friendly anticorrosive polymeric coatings. Firstly, the economic and environmental impact of corrosion is presented to highlight the need of anticorrosive polymeric coatings as a flexible and effective solution to protect a metal. Secondly, the implementation of regulations together with the consumer awareness for environmental considerations and protection of health are the driving force for a progressive but significant change in the sector. Therefore, within the protective organic coatings market, this article provides a review of the most recent developments in environmentally friendly solutions, including bio-based and water-borne epoxy, hyperbranched polyester for low- volatile organic compounds (VOC) coatings, waterborne polyurethane and non-isocyanate polyurethanes (NIPUs), and graphene or bio-based fillers for acrylics. Moreover, this paper outlines new trends such as smart additives, bio-based corrosion inhibitors, and functional antibiocorrosive coatings as superhydrophobics. Finally, industrially relevant applications of environmentally friendly anticorrosive polymeric coatings including solutions for marine and off-shore industries are summarized.

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Mahmood, Wafaa K., Wafaa A. Khadum, E. Eman y Hayder A. Abdulbari. "Biopolymer–Surfactant Complexes as Flow Enhancers: Characterization and Performance Evaluation". Applied Rheology 29, n.º 1 (1 de marzo de 2019): 12–20. http://dx.doi.org/10.1515/arh-2019-0002.

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AbstractArtificial polymeric additives are known, and experimentally proven, to be effective drag reducing agents in pipelines with turbulent flow medium. The artificial nature of these additives and their low resistance to high shear forces, exerted by the pipeline geometries and equipment, are considered as major problems against a wider implementation in other industrial applications. The present work introduces a new polymer-surfactant complex of two organic additives (chitosan and sodium laurel ether sulfate, SLES) as a drag reducing agent. The rheological and morphological properties of the new complexes were experimentally tested. The new complex’s drag reduction performance and stability against high shear forces were analyzed using rotating disk apparatus. All the investigated solutions and complexes showed a non-Newtonian behavior. The cryo-TEM images showed a unique polymer-surfactant macrocomplex structure with a nonlinear relationship between its rheological properties and surfactant concentration. A maximum flow enhancement of 47.75% was obtained by the complex (chitosan 300 and 400ppmof chitosan and SLES, respectively) at the rotation speed of 3000 rpm. Finally, the stability of the proposed additives was highly modified when the additive complexes were formed.

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Carotenuto, G., M. L. Nadal, P. Repetto, P. Perlo, L. Ambrosio y L. Nicolais. "New Polymeric Additives for Allowing Photoelectric Sensing of Plastics during Manufacturing". Advanced Composites Letters 16, n.º 3 (mayo de 2007): 096369350701600. http://dx.doi.org/10.1177/096369350701600303.

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Metallic mercaptides are inert organic compounds (i.e., Mex( SR) y) that can be used to make thermoplastic polymers high luminescent to UV-light. Luminescence is strictly required in polymer manufacturing since this characteristic allows detection of polymer pieces by photoelectric sensors. Luminescent Au, CdS, and ZnS nanoparticles can be generated into thermoplastics like: polystyrene, polycarbonate, poly(vinyl acetate), etc. by thermolysis of the corresponding mercaptides. PL spectra of polymeric films embedding these nanoparticles show intensive visible light emission in different spectral regions. The formation of nanoparticles was probably related to the viscous nature of reaction medium which significantly limit the growth stage.

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Morales-Jiménez, Mónica, Daniel A. Palacio, Manuel Palencia, Manuel F. Meléndrez y Bernabé L. Rivas. "Bio-Based Polymeric Membranes: Development and Environmental Applications". Membranes 13, n.º 7 (27 de junio de 2023): 625. http://dx.doi.org/10.3390/membranes13070625.

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Nowadays, membrane technology is an efficient process for separating compounds with minimal structural abrasion; however, the manufacture of membranes still has several drawbacks to being profitable and competitive commercially under an environmentally friendly approach. In this sense, this review focuses on bio-based polymeric membranes as an alternative to solve the environmental concern caused by the use of polymeric materials of fossil origin. The fabrication of bio-based polymeric membranes is explained through a general description of elements such as the selection of bio-based polymers, the preparation methods, the usefulness of additives, the search for green solvents, and the characterization of the membranes. The advantages and disadvantages of bio-based polymeric membranes are discussed, and the application of bio-based membranes to recover organic and inorganic contaminants is also discussed.

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Krutilin, A. N., Yu Yu Huminski, O. A. Rusevitch y L. V. Kulbitskaya. "IMPROVEMENT OF EFFICIENCY OF USE OF LIQUID-GLASS MIXTURES. OVERVIEW INFORMATION. PART 1. MODIFICATION". Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), n.º 1 (6 de abril de 2018): 47–54. http://dx.doi.org/10.21122/1683-6065-2018-1-47-54.

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The basic directions of improvement of properties of silicate binders and mixtures on their basis are generalized. Organic and inorganic additives for liquid-glass mixtures and autoclave modification are considered. A huge number of various additives proposed to improve the knockout rate of liquid-glass mixtures is due to the complexity of the processes occurring in the mixtures at high-temperature exposure. In order to obtain the optimal structure, it is necessary to ensure the presence in the silicate solution of colloidal particles of liquid glass and active functional groups of a polymeric modifier capable of interacting with this surface.

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Krasnopeeva, Elena L., Gaiane G. Panova y Alexander V. Yakimansky. "Agricultural Applications of Superabsorbent Polymer Hydrogels". International Journal of Molecular Sciences 23, n.º 23 (1 de diciembre de 2022): 15134. http://dx.doi.org/10.3390/ijms232315134.

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This review presents data from the past five years on the use of polymeric superabsorbent hydrogels in agriculture as water and nutrient storage and retention materials, as well as additives that improve soil properties. The use of synthetic and natural polymeric hydrogels for these purposes is considered. Although natural polymers, such as various polysaccharides, have undoubted advantages related to their biocompatibility, biodegradability, and low cost, they are inferior to synthetic polymers in terms of water absorption and water retention properties. In this regard, the most promising are semi-synthetic polymeric superabsorbents based on natural polymers modified with additives or grafted chains of synthetic polymers, which can combine the advantages of natural and synthetic polymeric hydrogels without their disadvantages. Such semi-synthetic polymers are of great interest for agricultural applications, especially in dry regions, also because they can be used to create systems for the slow release of nutrients into the soil, which are necessary to increase crop yields using environmentally friendly technologies.

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Hadi, Angham G., Emad Yousif, Gamal A. El-Hiti, Dina S. Ahmed, Khudheyer Jawad, Mohammad Hayal Alotaibi y Hassan Hashim. "Long-Term Effect of Ultraviolet Irradiation on Poly(vinyl chloride) Films Containing Naproxen Diorganotin(IV) Complexes". Molecules 24, n.º 13 (28 de junio de 2019): 2396. http://dx.doi.org/10.3390/molecules24132396.

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As poly(vinyl chloride) (PVC) photodegrades with long-term exposure to ultraviolet radiation, it is desirable to develop methods that enhance the photostability of PVC. In this study, new aromatic-rich diorganotin(IV) complexes were tested as photostabilizers in PVC films. The diorganotin(IV) complexes were synthesized in 79–86% yields by reacting excess naproxen with tin(IV) chlorides. PVC films containing 0.5 wt % diorganotin(IV) complexes were irradiated with ultraviolet light for up to 300 h, and changes within the films were monitored using the weight loss and the formation of specific functional groups (hydroxyl, carbonyl, and polyene). In addition, changes in the surface morphologies of the films were investigated. The diorganotin(IV) complexes enhanced the photostability of PVC, as the weight loss and surface roughness were much lower in the films with additives than in the blank film. Notably, the dimethyltin(IV) complex was the most efficient photostabilizer. The polymeric film containing this complex exhibited a morphology of regularly distributed hexagonal pores, with a honeycomb-like structure—possibly due to cross-linking and interactions between the additive and the polymeric chains. Various mechanisms, including direct absorption of ultraviolet irradiation, radical or hydrogen chloride scavenging, and polymer chain coordination, could explain how the diorganotin(IV) complexes stabilize PVC against photodegradation.

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Thomas, Ananya, Malavika Arun, Khalid Moinuddin y Paul Joseph. "Mechanistic Aspects of Condensed- and Gaseous-Phase Activities of Some Phosphorus-Containing Fire Retardants". Polymers 12, n.º 8 (11 de agosto de 2020): 1801. http://dx.doi.org/10.3390/polym12081801.

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As a part of our ongoing investigations on passively fire protecting polymeric materials, we have been employing both reactive and additive routes involving phosphorus-containing compounds. These included inorganic and organic substances, and in the latter case, the phosphorus-bearing groups differed in terms of the chemical environments (phosphite, phosphate, phosphine, phosphine oxide and phosphonate ester) and oxidation state of the P atom (i.e., III, or V). The overall flammability profiles of wood substrates coated with the phosphorus-containing compounds were obtained through cone calorimetric measurements. The elemental composition, morphology and chemical natures of the char residues, obtained from the cone tests, were analysed through a variety of spectroscopic, chromatographic and spectrometric means. From the complementary information, obtained through these analyses, some probable mechanistic pathways that underpin the condensed- and gaseous-phase activities of the different additives are suggested. It was found that the inorganic solid additive, i.e., (NH4)2HPO4, underwent a two-step degradation, yielding ammonia gas and phosphoric acid. Furthermore, the liquid additives, owing to their volatility as compared to the solid ones, showed a relatively higher presence in the vapour phase than volatile fragments emanating from the latter ones (i.e., from phosphine and the phosphine oxides).

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Mercea, P. V., C. Losher, M. Herburger, O. G. Piringer, V. Toşa, M. Cassart, G. Dawkins y B. Faust. "Repeated migration of additives from a polymeric article in food simulants". Polymer Testing 85 (mayo de 2020): 106436. http://dx.doi.org/10.1016/j.polymertesting.2020.106436.

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Zárybnická, Lucie, Radek Ševčík, Jaroslav Pokorný, Dita Machová, Eliška Stránská y Jiří Šál. "CaCO3 Polymorphs Used as Additives in Filament Production for 3D Printing". Polymers 14, n.º 1 (4 de enero de 2022): 199. http://dx.doi.org/10.3390/polym14010199.

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Nowadays, additive manufacturing—also called 3D printing—represents a well-established technology in the field of the processing of various types of materials manufacturing products used in many industrial sectors. The most common type of 3D printing uses the fused filament fabrication (FFF) method, in which materials based on thermoplastics or elastomers are processed into filaments. Much effort was dedicated to improving the properties and processing of such printed filaments, and various types of inorganic and organic additives have been found to play a beneficial role. One of them, calcium carbonate (CaCO3), is standardly used as filler for the processing of polymeric materials. However, it is well-known from its different applications that CaCO3 crystals may represent particles of different morphologies and shapes that may have a crucial impact on the final properties of the resulting products. For this reason, three different synthetic polymorphs of CaCO3 (aragonite, calcite, and vaterite) and commercially available calcite powders were applied as fillers for the fabrication of polymeric filaments. Analysis of obtained data from different testing techniques has shown significant influence of filament properties depending on the type of applied CaCO3 polymorph. Aragonite particles showed a beneficial impact on the mechanical properties of produced filaments. The obtained results may help to fabricate products with enhanced properties using 3D printing FFF technology.

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Vikhareva, Irina N., Guliya K. Aminova, Alexander I. Moguchev y Aliya K. Mazitova. "The Effect of a Zinc-Containing Additive on the Properties of PVC Compounds". Advances in Polymer Technology 2021 (15 de abril de 2021): 1–14. http://dx.doi.org/10.1155/2021/5593184.

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Polymeric materials that undergo degradation under the influence of biological media have attracted widespread attention in recent decades. This is due to the ability to eliminate the negative impact on the environment, gradually reducing the scale of plastic waste pollution. At the same time, it remains relevant to ensure the necessary performance characteristics of products for a certain period of use. An important direction in the field of biodegradable composite compositions is the development of nontoxic additives in order to ensure their safe interaction with biological media. In this regard, a method has been developed for the joint production of a new nontoxic plasticizer decyl phenoxyethyl adipate and a biocidal additive of zinc decyl adipate. The effect of the obtained additives on the biodegradation of PVC film samples under natural conditions was studied. The period of biocidal action of zinc compound formed in situ in an amount of 0.3% in the composition of PVC films using the developed plasticizer was determined.

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Hobbs, Christopher. "Recent Advances in Bio-Based Flame Retardant Additives for Synthetic Polymeric Materials". Polymers 11, n.º 2 (31 de enero de 2019): 224. http://dx.doi.org/10.3390/polym11020224.

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It would be difficult to imagine how modern life across the globe would operate in the absence of synthetic polymers. Although these materials (mostly in the form of plastics) have revolutionized our daily lives, there are consequences to their use, one of these being their high levels of flammability. For this reason, research into the development of flame retardant (FR) additives for these materials is of tremendous importance. However, many of the FRs prepared are problematic due to their negative impacts on human health and the environment. Furthermore, their preparations are neither green nor sustainable since they require typical organic synthetic processes that rely on fossil fuels. Because of this, the need to develop more sustainable and non-toxic options is vital. Many research groups have turned their attention to preparing new bio-based FR additives for synthetic polymers. This review explores some of the recent examples made in this field.

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Loukelis, Konstantinos, Zina A. Helal, Antonios G. Mikos y Maria Chatzinikolaidou. "Nanocomposite Bioprinting for Tissue Engineering Applications". Gels 9, n.º 2 (24 de enero de 2023): 103. http://dx.doi.org/10.3390/gels9020103.

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Bioprinting aims to provide new avenues for regenerating damaged human tissues through the controlled printing of live cells and biocompatible materials that can function therapeutically. Polymeric hydrogels are commonly investigated ink materials for 3D and 4D bioprinting applications, as they can contain intrinsic properties relative to those of the native tissue extracellular matrix and can be printed to produce scaffolds of hierarchical organization. The incorporation of nanoscale material additives, such as nanoparticles, to the bulk of inks, has allowed for significant tunability of the mechanical, biological, structural, and physicochemical material properties during and after printing. The modulatory and biological effects of nanoparticles as bioink additives can derive from their shape, size, surface chemistry, concentration, and/or material source, making many configurations of nanoparticle additives of high interest to be thoroughly investigated for the improved design of bioactive tissue engineering constructs. This paper aims to review the incorporation of nanoparticles, as well as other nanoscale additive materials, to printable bioinks for tissue engineering applications, specifically bone, cartilage, dental, and cardiovascular tissues. An overview of the various bioinks and their classifications will be discussed with emphasis on cellular and mechanical material interactions, as well the various bioink formulation methodologies for 3D and 4D bioprinting techniques. The current advances and limitations within the field will be highlighted.

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Hummel, Darius, Andreas Fath, Thilo Hofmann y Thorsten Hüffer. "Additives and polymer composition influence the interaction of microplastics with xenobiotics". Environmental Chemistry 18, n.º 3 (2021): 101. http://dx.doi.org/10.1071/en21030.

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Environmental contextThe effects of the presence of polymer additives and polymeric structure on sorption of xenobiotics to microplastics remain unclear. Our results combined data from experimental sorption batch experiments using three environmentally relevant model sorbates with confocal microscopy. This provides clear evidence that both factors play a major role in sorption strength and the underlying sorption process, affecting sorption onto the particle surface and partitioning into the bulk polymer. AbstractMicroplastics are particulate contaminants of global concern. Interactions of microplastics with organic contaminants are frequently studied with commercially available polymer materials as surrogates. The influence of the polymer structure (i.e. internal 3D polymer geometry and monomer chain length) and the presence of additives on their interactions with xenobiotics remains unclear. This work investigates sorption of three sorbates of environmental concern to two polyamide (PA) and two polyvinyl chloride (PVC) sorbents of different molecular composition and additive content, respectively. Sorption was studied using complementary data from sorption isotherms and confocal laser-scanning microscopy. The additives in PVC increased sorption affinity owing to an increased sorbent hydrophobicity and a higher void volume within the polymer. Surface area normalisation indicated surface adsorption for unplasticised PVC and absorption for 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH)-plasticised PVC, which were confirmed using confocal laser-scanning microscopy. The strong sorption to PA was mainly driven by hydrogen-bond interactions. The contribution depended on the molecular features of the sorbent and the sorbate. Confocal laser-scanning microscopy showed that PA6 was taking up more sorbate into its bulk polymer matrix than PA12, the two being different in their chemical composition. This difference could be attributed to the higher swelling capability of PA6. The results emphasise that the molecular structure of the polymer and the presence of additives have to be taken into consideration when sorption of organic substances to plastics is investigated.

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Kim, Tae Hoon, Seung Hyeon Park, Seoku Lee, A. V. S. L. Sai Bharadwaj, Yang Soo Lee, Chang Geun Yoo y Tae Hyun Kim. "A Review of Biomass-Derived UV-Shielding Materials for Bio-Composites". Energies 16, n.º 5 (25 de febrero de 2023): 2231. http://dx.doi.org/10.3390/en16052231.

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The adverse effects of UV (ultraviolet) radiation on polymeric materials and organic constituents can damage the molecular structure of human skin and polymeric materials, resulting in their degradation. Therefore, additives or reagents for UV-shielding must be used in related applications, including polymer compounds and skin cosmetics. Bio-based polymers have shown great potential as alternatives to conventional metallic and organic materials (e.g., TiO2 and ZnO) in various applications; therefore, natural products have gained attention as a potential resource to overcome UV-induced health and environmental problems. In particular, biomass-derived materials such as lignin, fiber, and silica have been investigated as UV-shielding materials owing to their biocompatibility, biodegradability, and low carbon emissions. In this review, the UV-shielding effect and potential of various biomass-derived materials, such as silica, nanocellulose, and fibers, are reviewed. Among them, lignin is considered a promising UV-shielding material because of the presence of chromophores and functional groups capable of absorbing UV radiation of all ranges.

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Lattimer, Robert P. "Direct Analysis of Elastomer Compounds by Soft Ionization, Tandem (MS/MS) and High Resolution (AC-MS) Mass Spectrometry". Rubber Chemistry and Technology 68, n.º 5 (1 de noviembre de 1995): 783–93. http://dx.doi.org/10.5254/1.3538774.

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Abstract In recent years very effective mass spectrometric methods have been developed for direct polymer compound analysis. The high sensitivity, high specificity, and superb mixture analysis capabilities of modern mass spectrometry make it an invaluable tool in the polymer industry, particularly for qualitative analysis (chemical identification) of organic additives as well as polymeric components. “Survey” mass spectra obtained with soft ionization methods — field ionization (FI-MS) and chemical ionization (CI-MS) — provide diagnostic overviews of chemical composition. The supplemental tandem (MS/MS) and atomic composition (AC-MS) techniques are used to make specific identifications of various organic ingredients. This report describes the direct mass spectrometric analysis of three different elastomer compounds. Organic additives, including curatives, were identified via thermal desorption methods in a commercial EPDM bearing as well as a diene rubber V-belt. The composition of a commercial thermoplastic polyurethane was determined via pyrolysis (Py-CI-MS). These problem-solving examples illustrate the very effective role that mass spectrometry can play in the industrial polymer analysis laboratory.

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24

Cook, Simon y Roy Lehrle. "Characterization and analysis of polymeric additives in oils by pyrolysis-g.c." European Polymer Journal 29, n.º 1 (enero de 1993): 1–8. http://dx.doi.org/10.1016/0014-3057(93)90264-g.

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25

HAN, Haifeng, Qing WANG, Xia LIU y Shengxiang JIANG. "Highly efficient and rapid capillary electrophoretic analysis of seven organic acid additives in beverages using polymeric ionic liquid as additive". Chinese Journal of Chromatography 30, n.º 5 (15 de septiembre de 2013): 538–42. http://dx.doi.org/10.3724/sp.j.1123.2011.12013.

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26

Singh, Bimal P., Sarama Bhattacharjee, Laxmidhar Besra, Dilip K. Sengupta y Vibhuti N. Misra. "Use of Polymeric and other Organic Additives in Ceramic Slurry Processing for Casting—A Review". Transactions of the Indian Ceramic Society 63, n.º 1 (enero de 2004): 1–8. http://dx.doi.org/10.1080/0371750x.2004.11012121.

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27

Wen, Hong, Kenneth R. Morris y Kinam Park. "Synergic Effects of Polymeric Additives on Dissolution and Crystallization of Acetaminophen". Pharmaceutical Research 25, n.º 2 (20 de octubre de 2007): 349–58. http://dx.doi.org/10.1007/s11095-007-9468-0.

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28

Hernández-Fernández, Joaquín, Esneyder Puello-Polo y Edgar Marquez. "Identifying, Quantifying, and Recovering a Sorbitol-Type Petrochemical Additive in Industrial Wastewater and Its Subsequent Application in a Polymeric Matrix as a Nucleating Agent". Molecules 28, n.º 13 (23 de junio de 2023): 4948. http://dx.doi.org/10.3390/molecules28134948.

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Currently, polypropylene (PP) is highlighted using sorbitol-based clarifying agents since these agents are high quality, low cost, and work as a barrier against moisture, which makes PP ideal for packaging food, beverages, and medical products, among others. The use of analytical methods capable of recovering these additives in wastewater streams and then reusing them in the PP clarification stage represents an innovative methodology that makes a substantial contribution to the circular economy of the PP production industry. In this study, a method of extraction and recovery of the Millad NX 8000 was developed. The additive was recovered using GC-MS and extracted with an activated carbon column plus glass fiber, using an injection molded sample, obtaining a recovery rate greater than 96%. TGA, DSC, and FTIR were used to evaluate the recovered additive’s glass transitions and purity. The thermal degradation of the recovered additive was found to be between 340 and 420 °C, with a melting temperature of 246 °C, adopting the same behavior as the pure additive. In FTIR, the characteristic absorption peak of Millad NX 8000 was observed at 1073 cm−1, which indicates the purity of the extracted compound. Therefore, this work develops a new additive recovery methodology with high purity to regulate the crystallization behavior and of PP.

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El-Hiti, Gamal, Mohammad Alotaibi, Ahmed Ahmed, Basheer Hamad, Dina Ahmed, Ahmed Ahmed, Hassan Hashim y Emad Yousif. "The Morphology and Performance of Poly(Vinyl Chloride) Containing Melamine Schiff Bases against Ultraviolet Light". Molecules 24, n.º 4 (22 de febrero de 2019): 803. http://dx.doi.org/10.3390/molecules24040803.

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Five Schiff bases derived from melamine have been used as efficient additives to reduce the process of photodegradation of poly(vinyl chloride) films. The performance of Schiff bases has been investigated using various techniques. Poly(vinyl chloride) films containing Schiff bases were irradiated with ultraviolet light and any changes in their infrared spectra, weight, and the viscosity of their average molecular weight were investigated. In addition, the surface morphology of the films was inspected using a light microscope, atomic force microscopy, and a scanning electron micrograph. The additives enhanced the films resistance against irradiation and the polymeric surface was much smoother in the presence of the Schiff bases compared with the blank film. Schiff bases containing an ortho-hydroxyl group on the aryl rings showed the greatest photostabilization effect, which may possibly have been due to the direct absorption of ultraviolet light. This phenomenon seems to involve the transfer of a proton as well as several intersystem crossing processes.

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30

ABURIDEH, HANANE, ZAHIA TIGRINE, LAMINE AOUDJIT, ZOUBIR BELGROUN, KAOUTHER REDJIMI y DJILLALI TASSALIT. "DEVELOPMENT OF ACID MODIFIED CELLULOSE ACETATE MEMBRANES FOR SALT WATER TREATMENT". Cellulose Chemistry and Technology 55, n.º 9-10 (3 de diciembre de 2021): 1153–61. http://dx.doi.org/10.35812/cellulosechemtechnol.2021.55.99.

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The main objective of this work has been to study the performance of membranes developed for water treatment. Polymeric membranes (CTP and CTP-Acid) were developed from solutions containing cellulose acetate (CA), cellulose triacetate (CTA) and polysulfone (PSF), using maleic acid (MA) and acetic acid (AA) as additives and chloroform/dioxane as solvent. The NIPS-type phase inversion method was chosen as the membrane film manufacturing technique. The incorporation of 2.5% and 5% by weight of acids in the membrane mixture allowed us to study the additive effect on the morphological structure, and to predict the performance of the membranes formed. The characterization of the membranes was performed by SEM and FTIR analyses. Examining the flux, permeability and selectivity of the membranes also permitted to study the efficiency and performance of each membrane. The addition of AA and MA additives within the mixture increased the hydrophilic character and improved the flux rate by increasing it from 75 Lm-2h-1 to 142.74 Lm-2h-1 for 5% maleic acid addition. The 5% CTP AA membrane gave very satisfactory results in terms of selectivity, with a maximum removal of 84% of NaCl salt. Therefore, this membrane has been considered to be the most efficient one, with a flux of 120 Lm-2h-1 to 15 bar and a NaCl salt retention that meets the standards required by the World Health Organization (WHO).

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31

Arahman, Nasrul, Sri Mulyati, Afrillia Fahrina, Syawaliah Muchtar, Mukramah Yusuf, Ryosuke Takagi, Hideto Matsuyama, Nik Abdul Hadi Nordin y Muhammad Roil Bilad. "Improving Water Permeability of Hydrophilic PVDF Membrane Prepared via Blending with Organic and Inorganic Additives for Humic Acid Separation". Molecules 24, n.º 22 (13 de noviembre de 2019): 4099. http://dx.doi.org/10.3390/molecules24224099.

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The removal of impurities from water or wastewater by the membrane filtration process has become more reliable due to good hydraulic performance and high permeate quality. The filterability of the membrane can be improved by having a material with a specific pore structure and good hydrophilic properties. This work aims at preparing a polyvinylidene fluoride (PVDF) membrane incorporated with phospholipid in the form of a 2-methacryloyloxyethyl phosphorylcholine, polymeric additive in the form of polyvinylpyrrolidone, and its combination with inorganic nanosilica from a renewable source derived from bagasse. The resulting membrane morphologies were analyzed by using scanning electron microscopy. Furthermore, atomic force microscopy was performed to analyze the membrane surface roughness. The chemical compositions of the resulting membranes were identified using Fourier transform infrared. A lab-scale cross-flow filtration system module was used to evaluate the membrane’s hydraulic and separation performance by the filtration of humic acid (HA) solution as the model contaminant. Results showed that the additives improved the membrane surface hydrophilicity. All modified membranes also showed up to five times higher water permeability than the pristine PVDF, thanks to the improved structure. Additionally, all membrane samples showed HA rejections of 75–90%.

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32

Abdel-Azim, Abdel-Azim A. y Rash M. Abdel-Aziem. "Polymeric additives for improving the flow properties and viscosity index of lubricating oils". Journal of Polymer Research 8, n.º 2 (junio de 2001): 111–18. http://dx.doi.org/10.1007/s10965-006-0140-x.

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Zimmermann, Matheus VG, Marcos Aurélio Colombo, Diego Pizza y Ademir J. Zattera. "Influence on the cross-linking and plasticization degree of poly(ethylene-co-vinyl acetate) and evaluation of expansion capacity to the production of foams with supercritical CO2". Progress in Rubber, Plastics and Recycling Technology 35, n.º 1 (13 de diciembre de 2018): 23–40. http://dx.doi.org/10.1177/1477760618797539.

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The modification of a thermoplastic elastomer by cross-linking or plasticizing allows the manipulation of material properties for different applications. Cross-linking additives promote the increase of mechanical, thermal, and rheological properties, while the use of plasticizers has the opposite effect, giving the material soft properties. Such characteristics affect the development of polymeric foams directly, where the polymer matrix properties have large influence on the foaming capacity and morphology of the cells. This study investigated the use of cross-linking and plasticizer additives in ethylene-co-vinyl acetate copolymer, as well as its influence on the foaming capacity. The increasing content of cross-linking additive impacts on formation of preferentially closed cells, with high cell density and smaller size, while using plasticizers a higher occurrence of cell deformation and open cells was verified. The low formation of cells due to the decreasing of the polymer matrix thermal stability allows gases to escape during the processing and favors the cell coalescence effect. The foaming temperature is directly related to the polymer melt temperature, so, for the plasticizer-added samples, lower temperatures were required during the foaming than the samples with the cross-linking agent.

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Chauke, Nyiko M., Richard M. Moutloali y James Ramontja. "Influence of the Zeolite ZSM-22 Precursor on a UF-PES Selective Substrate Layer for Salts Rejection". Membranes 12, n.º 6 (26 de mayo de 2022): 553. http://dx.doi.org/10.3390/membranes12060553.

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Fabrication of the ZSM-22/Polyethersulfone (ZSM-22/PES) membranes as selective salt filters represent a growing membrane technological area in separation with the potential of high economic reward based on its low energy requirements. The incorporation of ZSM-22 zeolite material as additives into the PES polymer matrix has the prospective advantage of combining both the zeolite and polymer features while overcoming the limitations associated with both materials. This work investigated the influence of the nature of the silica precursor on ZSM-22 zeolite hydrothermally synthesised using colloidal (C60) and fumed (C60) silica to Si/Al of 60. The successful synthesis of the highly crystalline zeolitic materials was confirmed through XRD, FTIR, and SEM with EDX. The ZSM-22 additives were directly dispersed into a PES polymeric matrix to form a casting solution for the preparation of the ZSM-22/PES selective substrate layers via a phase inversion method for salts rejection. The polymeric PES was selected as an organic network in which the content of the ZSM-22 zeolite (ranging between 0 and 1.0 wt.%), was obtained and characterised by XRD, FTIR, and SEM analysis, as well as water contact angle (WCA) measurement and dead-end filtration cell. The phase inversion preparation method has induced the resulting ZSM-22/PES NF substrates anisotropy, as attributed to a high water flux to the above 700 L·m−2·h−1; high selectivity and rejection of salts to above 80% is revealed by the obtained results. The materials also exhibited improved antifouling behavior to above 70% flux recovery ratios. As such, the nature of the silica precursor influences ZSM-22 zeolite synthesis as a potential additive in the PES polymer matrix and led to the enhanced performance of the pure PES ultrafiltration membrane.

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35

Stefas, Dimitrios, Nikolaos Gyftokostas, Elli Bellou y Stelios Couris. "Laser-Induced Breakdown Spectroscopy Assisted by Machine Learning for Plastics/Polymers Identification". Atoms 7, n.º 3 (19 de agosto de 2019): 79. http://dx.doi.org/10.3390/atoms7030079.

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In the present work, Laser-Induced Breakdown Spectroscopy (LIBS) is used for the discrimination/identification of different plastic/polymeric samples having the same polymeric matrix but containing different additives (as e.g., fillers, flame retardants, etc.). For the classification of the different plastic samples, some machine learning algorithms were employed for the analysis of the LIBS spectroscopic data, such as the Principal Component Analysis (PCA) and the Linear Discriminant Analysis (LDA). The combination of LIBS technique with these machine learning algorithmic approaches, in particular the latter, provided excellent classification results, achieving identification accuracies as high as 100%. It seems that machine learning paves the way towards the application of LIBS technique for identification/discrimination issues of plastics and polymers and eventually of other classes of organic materials. Machine learning assisted LIBS can be a simple to use, efficient and powerful tool for sorting and recycling purposes.

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Li, Xinyu, Zhongxin Zhang, Zheng Xie, Xinrui Guo, Tianjian Yang, Zhongli Li, Mei Tu y Huaxin Rao. "High Performance and Self-Humidifying of Novel Cross-Linked and Nanocomposite Proton Exchange Membranes Based on Sulfonated Polysulfone". Nanomaterials 12, n.º 5 (2 de marzo de 2022): 841. http://dx.doi.org/10.3390/nano12050841.

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The introduction of inorganic additive or nanoparticles into fluorine-free proton exchange membranes (PEMs) can improve proton conductivity and have considerable effects on the performance of polymer electrolyte membrane fuel cells. Based on the sol–gel method and in situ polycondensation, novel cross-linked PEM and nanocomposite PEMs based on a sulfonated polysulfone (SPSU) matrix were prepared by introducing graphene oxide (GO) polymeric brushes and incorporating Pt-TiO2 nanoparticles into an SPSU matrix, respectively. The results showed that the incorporation of Pt-TiO2 nanoparticles could obviously enhance self-humidifying and thermal stability. In addition, GO polymer brushes fixed on polymeric PEM by forming a cross-linked network structure could not only solve the leakage of inorganic additives during use and compatibility problem with organic polymers, but also significantly improve proton conductivity and reduce methanol permeability of the nanocomposite PEM. Proton conductivity, water uptake and methanol permeability of the nanocomposite PEM can be up to 6.93 mS cm−1, 46.58% and be as low as 1.4157 × 10−6 cm2 s−1, respectively, which represent increases of about 70%, about 22% and a decrease of about 40%, respectively, compared with that of primary SPSU. Therefore, the synergic action of the covalent cross-linking, GO polymer brush and nanoparticles can significantly and simultaneously improve the overall performance of the composite PEM.

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37

Nawaz, Muddasir, Nazal Naeem, Ramazan Kahraman, M. F. Montemor, W. Haider y R. A. Shakoor. "Effectiveness of Epoxy Coating Modified with Yttrium Oxide Loaded with Imidazole on the Corrosion Protection of Steel". Nanomaterials 11, n.º 9 (3 de septiembre de 2021): 2291. http://dx.doi.org/10.3390/nano11092291.

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The search for highly effective corrosion protection solutions to avoid degradation of the metallic parts is enabling the development of polymeric organic coatings. Of particular relevance, polymeric nanocomposite coatings, modified with corrosion inhibitors, have been developed to provide enhanced surface protection. In this work, yttrium oxide nanoparticles loaded with corrosion inhibitor (Imidazole), used as additives in the formulation of epoxy for coated on the steel substrate. The loading of Y2O3 with imidazole was confirmed by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller analysis. UV-Vis analysis demonstrated the pH-sensitive behavior of the imidazole that helps in self-release when necessary. Electrochemical impedance spectroscopy (EIS) of the coated samples revealed that the coating modified with Y2O3/IMD provides better corrosion protection compared to coatings containing only Y2O3. XPS analysis validated the presence of an imidazole protective film on the steel substrate that enhanced the corrosion resistance of the coated samples

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Brahim, Sean y Stefan Maat. "Binder-Free Cathode Enabling High Capacity Li-Ion Battery". ECS Meeting Abstracts MA2022-01, n.º 2 (7 de julio de 2022): 379. http://dx.doi.org/10.1149/ma2022-012379mtgabs.

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Li-ion batteries have polymeric binder in their electrodes resulting in high internal resistance and hence long charge times and compromised product lifetime. We have developed Li-ion batteries utilizing binder-free NMC cathodes containing carbon nanotube (CNT). Our proprietary processing of CNT into viscous organic or water-based slurry without surfactant or dispersant reduces or eliminates the need for organic binder and carbon black additives in these cathodes. The benefits of incorporating our processed CNT slurry into NMC cathode electrodes are realized by significant gains in specific energy and power. When the organic binder in the cathode is completely removed, our Li-ion batteries retain superior performance metrics over conventional binder-containing cells, including significantly reduced impedance (-31%) and increased capacity (5%). Li-ion pouch cells containing these binder-free NMC/CNT cathodes show 2.5% higher specific energy. Our cells with binder-free cathode complete 500 cycles with 50% less capacity fade than cells with binder, and display more than 2x improvement in capacity at 10C rate discharge. A processing advantage of eliminating the polymeric binder from the formulation mix was demonstrated by the use of IPA as dispersing solvent in place of the costlier and toxic NMP solvent. Li-ion cells containing binder-free NMC/CNT cathodes from IPA mix preserved their performance advantages over conventional NMP-based binder-containing cells. Figure 1

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39

Vuono, Danilo, Gabriele Clarizia, Loredana Ferreri, Grazia Maria Letizia Consoli, Daniela Clotilde Zampino, Giuseppina Scalzo, Salvatore Petralia y Paola Bernardo. "Molecularly Mixed Composite Membranes for Gas Separation Based on Macrocycles Embedded in a Polyimide". Polymers 16, n.º 4 (7 de febrero de 2024): 460. http://dx.doi.org/10.3390/polym16040460.

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Polyimides are a polymer class that has been extensively investigated as a membrane material for gas separation owing to its interesting permselective properties in a wide range of operation temperatures and pressures. In order to improve their properties, the addition of different filler types is currently studied. p-tert-Butylcalix[n]arene macrocycles (PTBCs) with different cavity sizes (PTBC4, PTBC6, PTBC8) were used as fillers in a commercial thermoplastic polyimide, with a concentration in the range 1–9 wt%, to develop nanocomposite membranes for gas separation. The selected macrocycles are attractive organic compounds owing to their porous structure and affinity with organic polymers. The nanocomposite membranes were prepared in the form of films in which the polymeric matrix is a continuous phase incorporating the dispersed additives. The preparation was carried out according to a pre-mixing approach in a mutual solvent, and the solution casting was followed by a controlled solvent evaporation. The films were characterized by investigating their miscibility, morphology, thermal and spectral properties. The gas transport through these films was examined as a function of the temperature and also time. The results evidenced that the incorporation of the chosen nanoporous fillers can be exploited to enhance molecular transport, offering additional pathways and promoting rearrangements of the polymeric chains.

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40

Abdul-Majeed, Mohammed Amer. "Preparation and Characterization of AgNp/PVDF Cmposite Ultrafiltration Membrane". Journal of Engineering 24, n.º 7 (29 de junio de 2018): 50. http://dx.doi.org/10.31026/j.eng.2018.07.04.

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In this study, polymeric ultrafiltration (UF) membranes were prepared by phase inversion method to obtain both antibacterial and organic antifouling properties. The membranes were cast from a solution of polyvinylidene fluoride (PVDF) and formative silver (Ag) nanoparticles were successfully immobilized on a polymer. This was done using a solvent N, N-dimethylformamide (DMF) which is a solvent for the PVDF polymer meanwhile it is a reducing agent for silver ion. The effect of silver nanoparticles additives on the performance of polymeric ultrafiltration membrane was verified. Chemical composition and morphology of the surfaces of the membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The antibacterial property of modified membrane and the influence of silver nanoparticles on pure water flux of composite membrane at 0.2 Mpa were also verified. The experimental results obtained concluded that the composite membrane properties have been improved by the integration of Ag nanoparticles. The grafted membrane with silver nanoparticles has shown a clear ability to inhibit the growth of E. coli, Pseudomonas Aeruginosa, and Bacillus Cereus. While the clean PVDF membrane (without any additives) did not show any effect of preventing the growth of these species of bacteria referred to above. The pure water flux, porosity and the mean pore size of composite membrane can reach 261.8 L/m2 h, 85.4%, and 0.0206 µm, respectively, and it was much more than that of pure PVDF membrane.

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41

Kazi, Salim N. "Fouling and fouling mitigation of calcium compounds on heat exchangers by novel colloids and surface modifications". Reviews in Chemical Engineering 36, n.º 6 (26 de agosto de 2020): 653–85. http://dx.doi.org/10.1515/revce-2017-0076.

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AbstractFouling is the accumulation of unwanted materials on surfaces that causes detrimental effects on its function. The accumulated materials can be composed of living organisms (biofouling), nonliving substances (inorganic and/or organic), or a combination of both of them. Mineral fouling occurs when a process uses cooling water supersaturated with mineral salt crystals (i.e. hard water). Precipitation ensues on heat transfer surfaces whenever the inversely soluble dissolved calcium salt ions are exposed to high temperature. Mineral salts, dirt, waxes, biofilms, whey proteins, etc. are common deposits on the heat exchanger surfaces, and they create thermal resistance and increase pressure drop and maintenance costs of plants. Fouling of dissolved salts and its mitigation have been studied in detail by varying process parameters, surface materials, coatings on surfaces, additives, etc. by many researchers. In the present stage, researchers have considered polymeric additives, environmental friendly nanoparticles, natural fibers, and thermal conductive coatings (metallic and polymeric) in the study of mitigation of fouling. A better understanding of the problem and the mechanisms that lead to the accumulation of deposits on surfaces will provide opportunities to reduce or even eliminate the problem in certain situations. The present review study has focused on fouling phenomena, environment of fouling, heat exchanger fouling in design, and mitigation of fouling. The findings could support in developing the improved heat exchanger material surfaces, retain efficiency of the heat exchangers, and prolong their continuous operation.

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42

Sansul, Shaymaa, Emad Yousif, Dina S. Ahmed, Gamal A. El-Hiti, Benson M. Kariuki, Hassan Hashim y Ahmed Ahmed. "Pendant Modification of Poly(methyl methacrylate) to Enhance Its Stability against Photoirradiation". Polymers 15, n.º 14 (9 de julio de 2023): 2989. http://dx.doi.org/10.3390/polym15142989.

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Photostabilization of functional polymeric materials is important for protection against aging and ultraviolet (UV) irradiation. There is, therefore, the impetus to modify polymers to increase their resistance to photodegradation and photooxidation on extended exposure to UV light in harsh conditions. Various polymeric additives have been designed and synthesized in recent years, and their potential as photostabilizers has been explored. Reported here is the effect of pendant functionalization of poly(methyl methacrylate) (PMMA) through organometallic moiety incorporation into the polymer’s backbone. The reaction of PMMA with ethylenediamine leads to the formation of an amino residue that can react with salicylaldehyde to produce the corresponding Schiff base. Adding metal chlorides (zinc, copper, nickel, and cobalt) led to the formation of organometallic residues on the polymeric chains. Thin films of modified and unmodified PMMA were produced and irradiated with UV light to determine the effect of pendant modification on photostability. The photostabilization of PMMA was assessed using a range of methods, including infrared spectroscopy, weight loss, decomposition rate constant, and surface morphology. The modified PMMA incorporating organic Schiff base metal complexes showed less photodecomposition than the unmodified polymer or one containing the Schiff base only. Thus, the metals significantly reduced the photodegradation of polymeric materials. The polymer containing the Schiff base-cobalt unit showed the least damage in the PMMA surface due to photoirradiation, followed by those containing nickel, zinc, and copper, in that order.

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43

Jasem, Hadeer, Angham G. Hadi, Gamal A. El-Hiti, Mohammed A. Baashen, Hassan Hashim, Ahmed A. Ahmed, Dina S. Ahmed y Emad Yousif. "Tin-Naphthalene Sulfonic Acid Complexes as Photostabilizers for Poly(vinyl chloride)". Molecules 26, n.º 12 (14 de junio de 2021): 3629. http://dx.doi.org/10.3390/molecules26123629.

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Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%–95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.

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44

Voznyakovskii, A. P., V. Kh Kudoyarova, M. F. Kudoyarov, V. M. Lebedev y V. T. Lebedev. "Specific Features of the Distribution of Modifying Fullerene Additives in Ultrathin Polymeric Films". Fullerenes, Nanotubes and Carbon Nanostructures 18, n.º 4-6 (22 de octubre de 2010): 437–40. http://dx.doi.org/10.1080/1536383x.2010.488175.

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45

Vidlička, Martin, Karol Balog, Aleš Dudáček y Dana Chudová. "Removal of Total Organic Carbon (TOC) from a Stationary Source using Diatomaceous Earth and Activated Carbon during the Processing of Polymeric Materials". International Journal of Emerging Technology and Advanced Engineering 12, n.º 10 (1 de octubre de 2022): 29–36. http://dx.doi.org/10.46338/ijetae1022_04.

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— Volatile organic compounds (VOCs) are among the most common pollutants released into the air in the petrochemical and chemical industries. The article deals with removing VOCs while producing plastic granules containing approx. 80% polypropylene and polyethene, together with other additives. In this sector, the simplifying factor is that it deals with only one volatile pollutant, total organic carbon TOC, regardless of the specific materials from which the VOC emission originates. The permissible pollution level indicates a TOC emission limit of 50 mg ∙ m-3 for this production. During operation, emissions are extracted from the machinery to a stationary source. It is a fabric filter where the air is cleaned through a layer of diatomaceous earth. To determine if the above limit is not exceeded, measurements showed that the TOC limits are significantly higher (82.9 mg m-3 ). Therefore, tests were carried out using a mixture of activated carbon and diatomaceous earth. The results showed that activated carbon significantly reduced TOC concentrations to 8.4 mg m-3 . Keywords— Activated carbon, diatomaceous earth, polymers, stationary source, total organic carbon, TOC, volatile organic compounds, VOC.

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46

Kuksenko, S. P., H. O. Kaleniuk, Yu O. Tarasenko y M. T. Kartel. "Influence of electrolyte additive of trimethylsilylisocyanate on properties of electrode with nanosilicon for lithium-ion batteries". Himia, Fizika ta Tehnologia Poverhni 12, n.º 1 (30 de marzo de 2021): 67–78. http://dx.doi.org/10.15407/hftp12.01.067.

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Even partial replacement of graphite in the anode of lithium-ion batteries with silicon can significantly increase their specific energy. But the issue is the insufficient life cycle of such batteries due to the accelerated degradation of the liquid organic electrolyte with traditional lithium hexafluorophosphate, especially at elevated temperatures. The subject of discussions and further research are the processes involving a natural oxide layer on the surface of silicon in the manufacture and electrochemical litiation–delitiation of Si-containing electrodes. Among the most promising areas for solving the issues of practical application of silicon are new additives to the electrolyte and polymeric binders for electrode masses. This paper demonstrates the capability of trimethylsilylisocyanate (with aminosilane and isocyanate functional groups) as an additive to a liquid organic electrolyte (LiPF6 / fluoroethylene carbonate + ethyl methyl carbonate + vinylene carbonate + ethylene sulfite) to scavenge the reactive HF and PF5 species that alleviates the thermal decomposition of fluoroethylene carbonate at elevated temperatures. This makes it possible to increase the electrochemical parameters of half-cells with a hybrid graphite–nanosilicon working electrode when using water-based binders – carboxymethylcellulose and styrene-butadiene rubber. The addition of trimethylsilylisocyanate in the electrolyte significantly improves the reversible capacity of hybrid electrodes and reduces the accumulated irreversible capacity during prolonged cycling at normal temperature and after exposure at 50 °C, therefore to be effective for use in high-energy lithium-ion batteries.

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47

Agarwal, Deepa, William MacNaughtan, Roger Ibbett y Tim J. Foster. "Effect of moisture content on thermal and water absorption properties of microfibrillar cellulose with polymeric additives". Carbohydrate Polymers 211 (mayo de 2019): 91–99. http://dx.doi.org/10.1016/j.carbpol.2019.02.004.

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Lipponen, S. y J. Seppälä. "Ethylene/silane copolymers prepared with a metallocene catalyst as polymeric additives in polyethylene/aluminum trihydroxide composites". Journal of Polymer Science Part A: Polymer Chemistry 43, n.º 22 (2005): 5597–608. http://dx.doi.org/10.1002/pola.21037.

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Zhou, Xiaoqing, Qi Zhang, Rong Xu, Dong Chen, Shilong Hao, Fude Nie y Hongzhen Li. "A Novel Spherulitic Self-Assembly Strategy for Organic Explosives: Modifying the Hydrogen Bonds by Polymeric Additives in Emulsion Crystallization". Crystal Growth & Design 18, n.º 4 (16 de marzo de 2018): 2417–23. http://dx.doi.org/10.1021/acs.cgd.8b00044.

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50

Hodul, Jakub, Tomáš Žlebek, Lenka Mészárosová, Aleš Jakubík y Rostislav Drochytka. "Adhesives for the Installation of Cast Basalt Elements on Metal and Comparison of Properties when Using Different Types of Fillers". Key Engineering Materials 898 (27 de agosto de 2021): 35–41. http://dx.doi.org/10.4028/www.scientific.net/kem.898.35.

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Resumen

The polymeric adhesives for the installation of basalt elements on a metal base are designed primarily for environments with increased chemical and mechanical stress. They are composed of polymer resins (epoxy, polyurethane) as binders, as well as organic additives and mineral admixtures that mainly fulfill the function of filler. In all sectors of today's construction industry, maximum efficiency in the production of materials is required for sustainability purposes, which, however, must never be at the expense of the quality or the required performance. Due to these requirements, great emphasis is placed on the maximum use of secondary raw materials. Talc is used as the primary filler for polymer adhesives. Sawdust, tire rubber, and fly ash are used as secondary raw materials. The use of these in building supplies can positively affect some physical and mechanical properties of polymeric adhesives. Also, the use of secondary raw materials has the above-mentioned ecological benefit. Basic properties, such as bulk density and adhesion to both metallic and basalt elements, were monitored. The details of the cohesion of the adhesive with the bonded material, as well as the distribution of secondary raw materials in the polymer matrix, were assessed microscopically.

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