Polymers

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19 pages, 5864 KiB

Open AccessArticle

Testing of Polymer Composites for Manufacturing of Sprayer Nozzles

by Victoria E. Slavkina, Maksim A. Mirzaev, Anton M. Kuzmin, Alexey I. Kutyrev, Sergey P. Tuzhilin, Vyacheslav A. Denisov and Yuriy V. Kataev

Polymers 2024, 16(4), 496; https://doi.org/10.3390/polym16040496 - 10 Feb 2024

Viewed by 713

Abstract

Wear is the leading cause of nozzle failure. The durability of the nozzle is affected by the material it is made from. Traditional materials are ceramics, stainless steel, brass, and polymers. One of the possible ways to improve the wear resistance of polymer [...] Read more.

Wear is the leading cause of nozzle failure. The durability of the nozzle is affected by the material it is made from. Traditional materials are ceramics, stainless steel, brass, and polymers. One of the possible ways to improve the wear resistance of polymer nozzles is through the incorporation of dispersed fillers into them. This paper presents the results of testing polymer composites for their chemical resistance to pesticides, examining the effects of different types and amounts of fillers on the chemical and abrasion resistance. When silicon carbide was used as a filler, the strength increased by 30.2%. The experiments on chemical resistance to pesticides revealed that the nature, shape, and volume content of filler particles do not significantly affect the resistance of the compounds obtained. Tests on hydro-abrasive wear have shown that graphite and silicon carbide are effective fillers capable of reducing wear by up to 7.5 times. Based on previous research, it is recommended to use a composite compound with 15% volume of silicon carbide for nozzle manufacturing. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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15 pages, 8880 KiB

Open AccessArticle

Facile Preparation of PVDF/CoFe₂O₄-ZnO Hybrid Membranes for Water Depollution

by Adriana Popa, Maria Stefan, Sergiu Macavei, Ioana Perhaita, Lucian Barbu Tudoran and Dana Toloman

Polymers 2023, 15(23), 4547; https://doi.org/10.3390/polym15234547 - 27 Nov 2023

Viewed by 610

Abstract

In this investigation, CoFe₂O₄-PVDF and CoFe₂O₄-ZnO-PVDF hybrid membranes were prepared using a modified phase inversion method in which a magnetic field was applied during the casting process to ensure a uniform distribution of nanomaterials on [...] Read more.

In this investigation, CoFe₂O₄-PVDF and CoFe₂O₄-ZnO-PVDF hybrid membranes were prepared using a modified phase inversion method in which a magnetic field was applied during the casting process to ensure a uniform distribution of nanomaterials on the membrane surface. Thus, better absorption of light and increased participation of nanoparticles in the photodegradation process is ensured. The influence of nanomaterials on the crystalline structure, surface morphology, and hydrophilicity properties of the PVDF membrane was investigated. The obtained results indicated that the hybrid membrane exhibited significant differences in its intrinsic properties due to the nanomaterials addition. The hydrophilicity properties of the PVDF membrane were improved by the presence of nanoparticles. The photocatalytic decomposition of aqueous Rhodamine B solution in the presence of the prepared membrane and under visible light irradiation was tested. The hybrid membrane containing CoFe₂O₄-ZnO on its surface exhibited a high removal rate. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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20 pages, 4737 KiB

Open AccessArticle

Green Synthesis of Gold, Silver, Copper, and Magnetite Particles Using Poly(tartaric acid) Simultaneously as Coating and Reductant

by Alexander Bunge, Teodora Radu, Gheorghe Borodi, Sanda Boca and Alexandrina Nan

Polymers 2023, 15(23), 4472; https://doi.org/10.3390/polym15234472 - 21 Nov 2023

Viewed by 896

Abstract

Poly(tartaric acid) is a relatively recently described polymer that can be easily synthesized and scaled up from a readily available renewable material (tartaric acid). This article demonstrates its use in a green synthesis of gold nanoparticles, silver nanoparticles, copper particles, and magnetite nanoparticles. [...] Read more.

Poly(tartaric acid) is a relatively recently described polymer that can be easily synthesized and scaled up from a readily available renewable material (tartaric acid). This article demonstrates its use in a green synthesis of gold nanoparticles, silver nanoparticles, copper particles, and magnetite nanoparticles. In this case poly(tartaric acid) acts both as a reductant and as a coating agent. To our knowledge this is the first green synthesis of several different types of nanoparticles using only one reagent (polytartrate) as both reductant and coating. The resulting particles were analyzed by XRD, TEM/SEM, EDX, FTIR, DLS, zeta-potential, XPS, and UV/VIS spectroscopy. Preliminary studies of the thermal behavior of mixtures of different types of particles with poly(tartaric acid) were also conducted. The obtained particles show different sizes depending on the material, and the coating allows for better dispersibility as well as potential further functionalization, making them potentially useful also for other applications, besides the inclusion in polymer composites. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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15 pages, 5730 KiB

Open AccessArticle

Design and Analysis of a New Multi-Part Composite Frangible Cover

by Yuan Qian, Wenlong Li, Xiaopei Wang and Deng’an Cai

Polymers 2023, 15(15), 3307; https://doi.org/10.3390/polym15153307 - 4 Aug 2023

Viewed by 1023

Abstract

In this paper, a new multi-part composite frangible cover (MCFC) was designed and fabricated. The frangible cover, manufactured with a traditional manual lay-up method, is designed to conduct a simulated missile launch test using a specially developed test device. A weak zone structure [...] Read more.

In this paper, a new multi-part composite frangible cover (MCFC) was designed and fabricated. The frangible cover, manufactured with a traditional manual lay-up method, is designed to conduct a simulated missile launch test using a specially developed test device. A weak zone structure of the composite multi-part frangible cover was designed, and the separation process of the cover was studied by numerical simulation. Based on the strength envelope of the weak zone and the equal-strength design principle, a design method for the weak zone structure of the composite multi-part frangible cover was proposed. A finite element model of the composite multi-part frangible cover was established, and the separation process was numerically simulated and analyzed. Afterward, the verification experiments were carried out. Close agreements between the numerical and experimental results are observed. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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10 pages, 1324 KiB

Open AccessArticle

What Is Wrong with Hyaluronic Acid Chemistry? A ¹⁵N/¹³C Solid-State NMR Re-Evaluation of Its Dopamine Conjugates

by Ioana-Georgeta Grosu, Augustin Moț, Xenia Filip and Claudiu Filip

Polymers 2023, 15(13), 2825; https://doi.org/10.3390/polym15132825 - 26 Jun 2023

Viewed by 1120

Abstract

In this work, a systematic ¹⁵N/¹³C solid-state NMR investigation is performed on three dopamine (DA) conjugates of hyaluronic acid, considered in both its native (HA) and NaIO₄-oxidized (HA_Ox) forms. Two of them, here named HA_EDC [...] Read more.

In this work, a systematic ¹⁵N/¹³C solid-state NMR investigation is performed on three dopamine (DA) conjugates of hyaluronic acid, considered in both its native (HA) and NaIO₄-oxidized (HA_Ox) forms. Two of them, here named HA_EDC-DA and HA_Ox-DA, have been previously introduced as covalent conjugates involving DA amine nitrogen: the former by EDC-mediated amide bond formation, and the latter by reaction of the Schiff base with the aldehyde moieties presumed to exist in HA_Ox. The third conjugate, HA-DA, is reported here for the first time; it is obtained by simply mixing hyaluronan with DA∙HCl at pH 5. The ¹⁵N ss-NMR spectra were found to be consistent in all the systems, and the DA molecules were found to be in their charged -NH₃⁺ form, which contradicts the HA_EDC-DA/HA_Ox-DA covalent bonding schemes proposed in the literature. The ¹³C ss-NMR results add useful new insights into the structure and interaction patterns of the conjugates. All of our findings are relevant for future practical applications, for instance in developing novel HA-based hydrogels. In addition, the present study demonstrates the importance of using the most appropriate analytical tools when investigating composite systems due to the complexity of hyaluronic acid conjugates. Solid-state NMR proved essential to answering the question in the title: actually, there is nothing wrong with hyaluronic acid chemistry; the claimed covalent bonds between DA and the HA(HA_Ox) chain do not exist in these systems, because the conditions for their formation do not hold in practice. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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13 pages, 4122 KiB

Open AccessArticle

The Solution Properties of Polymethacrylate Molecular Brushes with Oligo(ethylene glycol) and Oligo(propylene glycol) Side Chains

by Maria Simonova, Alexander Simagin, Denis Kamorin, Sergey Orekhov, Alexander Filippov and Oleg Kazantsev

Polymers 2022, 14(24), 5556; https://doi.org/10.3390/polym14245556 - 19 Dec 2022

Cited by 2 | Viewed by 1597

Abstract

The properties of polymer brushes based on three macromonomers were investigated in aqueous and organic solutions. Methacrylic monomers with different compositions of the oligo(oxyalkylene) substituents and arrangements of the oligo(ethylene glycol) and oligo(propylene glycol) blocks were used for the synthesis of polymers. There [...] Read more.

The properties of polymer brushes based on three macromonomers were investigated in aqueous and organic solutions. Methacrylic monomers with different compositions of the oligo(oxyalkylene) substituents and arrangements of the oligo(ethylene glycol) and oligo(propylene glycol) blocks were used for the synthesis of polymers. There were methoxy [oligo(ethylene glycol)_10.3-block-oligo(propylene glycol)_4.7] methacrylate, methoxy [oligo(propylene glycol)_8.3-block-oligo(ethylene glycol)_6.6] methacrylate, and methoxy oligo(propylene glycol)_4.2 methacrylate. Molecular brushes were investigated by the methods of molecular hydrodynamics and optics in dilute solutions in acetonitrile, chloroform, and water. The peculiarities of behavior of poly[oligo(oxyalkylene) methacrylates] in aqueous solutions and water-toluene systems have been found; in particular, the solubility of the polymers in water and organic solvents, the polymers equilibrium distribution between the phases, and the surface activity in the water-toluene system have been established. The thermo-responsibility in aqueous solutions and values of a critical concentration of micelle formation were shown. Depending on the arrangement of blocks in the side chains of molecular brushes, they are characterized by different intramolecular density. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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11 pages, 854 KiB

Open AccessArticle

Compression Relaxation of Multi-Structure Polymer Composites in Penetrating Liquid Medium

by Alexander Kondratov, Valery Konyukhov, Stanislav Yamilinets, Ekaterina Marchenko and Gulsharat Baigonakova

Polymers 2022, 14(23), 5177; https://doi.org/10.3390/polym14235177 - 28 Nov 2022

Cited by 3 | Viewed by 1116

Abstract

Multi-structural polymer composites are widely used in the mechanical engineering, automotive, aviation and oil refining industries, as well as in the printing industry as a shock-absorbing deckle on the offset cylinders of printing machines. During offset printing, composites come into contact with inks [...] Read more.

Multi-structural polymer composites are widely used in the mechanical engineering, automotive, aviation and oil refining industries, as well as in the printing industry as a shock-absorbing deckle on the offset cylinders of printing machines. During offset printing, composites come into contact with inks and washing solutions, the components of which penetrate the material and cause the polymers to swell. This process degrades the print quality, and for this reason the study of its features is relevant. The prerequisites for this work are the study of the fundamental laws of diffusion and sorption of liquids by polymers with different micro- and macro-structures in different physical states and in different forms (e.g., films, sheets, fibers and fabrics). The combination of polymer materials in the composition of multi-structural fabric blankets makes it possible to obtain materials with unique mechanical properties and high resistance to liquid penetrating media and to use them in high-tech processes of multi-color printing with high resolution and color rendering. This article reports for the first time the kinetics and thermodynamics results obtained from the swelling of multi-structural polymeric blankets in solvents used in printing, and the effect of sorption of different polar liquids on the viscoelastic strain under compression during the operation of the damping systems of printing machines. Using mathematical models of activated liquid diffusion in polymers and deformation of a viscoelastic body, the swelling rate constants, solvent diffusion coefficients (the kinetic characteristics of the swelling process) and Flory–Huggins parameters (the thermodynamic characteristics of the interaction of the solvent with the composite) for composite–solvent systems with several chemical composition variants were determined. The elastic modulus and the viscosity coefficient of the composite under liquid saturation were calculated based on the experimental cyclic compression data. The range of change in the compression and restoration times of the polymeric blankets (0.09 s ÷ 0.78 s) was determined. It was shown that the composite swelled to a limited extent in all the studied liquids. All solvents used were thermodynamically poor (χ > 0.5). It has been established that rubber–fabric blankets coated with nitrile rubber are the least resistant to the action of dichloroethane, and that blankets with layers of polyolefins are not resistant to ethyl acetate. Water significantly affects the physicochemical properties of rubber–fabric blankets with a large proportion of cotton fabric layers. The data obtained can serve as a basis for optimizing the compositions of inks and cleaning solutions, as well as a theoretical basis for the thermodynamics of composite–solvent systems. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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Review

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39 pages, 8965 KiB

Open AccessReview

Self-Healing of Polymers and Polymer Composites

by Vadim I. Irzhak, Igor E. Uflyand and Gulzhian I. Dzhardimalieva

Polymers 2022, 14(24), 5404; https://doi.org/10.3390/polym14245404 - 9 Dec 2022

Cited by 18 | Viewed by 5221

Abstract

This review is devoted to the description of methods for the self-healing of polymers, polymer composites, and coatings. The self-healing of damages that occur during the operation of the corresponding structures makes it possible to extend the service life of the latter, and [...] Read more.

This review is devoted to the description of methods for the self-healing of polymers, polymer composites, and coatings. The self-healing of damages that occur during the operation of the corresponding structures makes it possible to extend the service life of the latter, and in this case, the problem of saving non-renewable resources is simultaneously solved. Two strategies are considered: (a) creating reversible crosslinks in the thermoplastic and (b) introducing a healing agent into cracks. Bond exchange reactions in network polymers (a) proceed as a dissociative process, in which crosslinks are split into their constituent reactive fragments with subsequent regeneration, or as an associative process, the limiting stage of which is the interaction of the reactive end group and the crosslink. The latter process is implemented in vitrimers. Strategy (b) is associated with the use of containers (hollow glass fibers, capsules, microvessels) that burst under the action of a crack. Particular attention is paid to self-healing processes in metallopolymer systems. Full article

(This article belongs to the Special Issue Challenges and Trends in Polymer Composites)

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