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15 pages, 2003 KB

Open AccessArticle

Synthesis of Vinyl-Containing MQ Copolymers in Active Medium

by Alina Khmelnitskaia, Aleksandra Kalinina, Ivan Meshkov, Ekaterina Ivanova, Sergey G. Vasil’ev, Alexander Buzin, Gagik Ghazaryan, Sergey Ponomarenko and Aziz Muzafarov

Polymers 2026, 18(3), 315; https://doi.org/10.3390/polym18030315 - 24 Jan 2026

Viewed by 670

Abstract

MQ copolymers, consisting of monofunctional (M) and tetrafunctional (Q) siloxane units, are versatile materials used as additives, adhesives, and in composite materials. Functional groups, such as vinyl substituents, in M-units allow for the tailoring of properties for specific applications. This study aimed to [...] Read more.

MQ copolymers, consisting of monofunctional (M) and tetrafunctional (Q) siloxane units, are versatile materials used as additives, adhesives, and in composite materials. Functional groups, such as vinyl substituents, in M-units allow for the tailoring of properties for specific applications. This study aimed to synthesize vinyl-containing MQ copolymers (M^VinMQ) via a controlled, chlorine-free method to explore the regulation of their composition and properties. The results demonstrated precise control over the copolymer architecture, with hydroxyl content and molecular weight increasing alongside the Q-unit fraction. All obtained copolymers exhibited high thermal stability, with 5% mass loss occurring above 295 °C in air and 365 °C in argon. Fractionation data supported a molecular composite model consisting of an inorganic core and an organic shell. Polycondensation in an active medium is an effective method for the directed synthesis of structurally tunable M^VinMQ copolymers, offering a versatile platform for developing functional hybrid materials, modifiers, and cross-linking agents. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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16 pages, 2100 KB

Open AccessArticle

Novel Core–Shell Nanostructure of ε-Poly-L-lysine and Polyamide-6 Polymers for Reusable and Durable Antimicrobial Function

by Saloni Purandare, Rui Li, Chunhui Xiang and Guowen Song

Polymers 2025, 17(23), 3195; https://doi.org/10.3390/polym17233195 - 30 Nov 2025

Viewed by 690

Abstract

Antimicrobial function in protective and medical textiles is an essential safety feature since textiles can become breeding grounds for microorganisms. Ideally, the antimicrobial function in textiles should be non-toxic, stable, and durable. This study explores a core–shell nanofiber with a core of the [...] Read more.

Antimicrobial function in protective and medical textiles is an essential safety feature since textiles can become breeding grounds for microorganisms. Ideally, the antimicrobial function in textiles should be non-toxic, stable, and durable. This study explores a core–shell nanofiber with a core of the cationic biopolymer ε-poly-L-lysine (PL) and shell of structurally similar and biocompatible polyamide-6 (PA). The core–shell structure is expected to have a more stable antimicrobial function than its monolithic counterpart. Further, thermal crosslinking is expected to prevent rapid diffusion of the water-soluble PL. Therefore, this study establishes a comparison between a monolithic (control), a core–shell (CS), and a thermally crosslinked core–shell (CL-CS) nanofiber of PL and PA. Morphological analysis confirmed the successful generation of the core–shell nanofibers. All the samples exhibited hydrophilic behavior and antimicrobial function. However, the control sample showcased significantly reduced zones of inhibition in antimicrobial testing with 21 days of bacterial exposure (1.027 ± 0.072 cm²), as compared to 24 h bacterial exposure (1.347 ± 0.151 cm²). On the other hand, the zones of inhibition for 24 h vs. 21 days for CS (1.265 ± 0.042 cm² vs. 1.052 ± 0.235 cm²) and CL-CS (1.128 ± 0.161 cm² vs. 1.106 ± 0.047 cm²) showed no significant differences. Therefore, the core–shell structure allowed for sustainable and durable antimicrobial action. Lastly, the CL-CS sample exhibited reusable antimicrobial function owing to the core–shell structure paired with thermal crosslinking. This study showcases a fiber system with non-toxic, durable, and reusable antimicrobial function. This study builds grounds for the development and multifaceted holistic characterization of safe, stable, and scalable antimicrobial textiles. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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13 pages, 5530 KB

Open AccessArticle

Investigation of Metallo(organo)siloxane—Polydimethylsiloxane Composites with a High Metallosiloxane Component Content

by Nadezhda A. Tebeneva, Alexander N. Tarasenkov, Ivan B. Meshkov, Aleksandra A. Kalinina, Alexander I. Buzin, Mikhail I. Buzin, Galina P. Goncharuk and Aziz M. Muzafarov

Polymers 2025, 17(22), 3034; https://doi.org/10.3390/polym17223034 - 16 Nov 2025

Viewed by 773

Abstract

A representative series of functional branched metallosiloxane oligomers was used to obtain polydimethylsiloxane-based composites highly filled with a metallosiloxane component. Physical and mechanical characteristics of compositions obtained strongly depends on metallosiloxane structure and composition. It is shown that it is possible to regulate [...] Read more.

A representative series of functional branched metallosiloxane oligomers was used to obtain polydimethylsiloxane-based composites highly filled with a metallosiloxane component. Physical and mechanical characteristics of compositions obtained strongly depends on metallosiloxane structure and composition. It is shown that it is possible to regulate the strength and elastic properties of the systems under consideration within wide limits, as well as to influence the morphology of the material. The resulting materials are rather thermo-oxidatively stable and can also maintain high mobility of polydimethylsiloxane chains. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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12 pages, 1282 KB

Open AccessArticle

Disposable Foamed Silicone Composite Actuator Powered by Sublimation

by Igor Bezsudnov, Alina Khmelnitskaia, Aleksandra Kalinina and Sergey Ponomarenko

Polymers 2025, 17(22), 3032; https://doi.org/10.3390/polym17223032 - 15 Nov 2025

Viewed by 651

Abstract

Soft actuators are widely explored as movers in various devices, human–machine interfaces, for medical purposes and other biomedical applications. Among them are soft actuators based on a foamed silicone matrix with the working liquid (WL) captured in its pores that undergo the liquid–gas [...] Read more.

Soft actuators are widely explored as movers in various devices, human–machine interfaces, for medical purposes and other biomedical applications. Among them are soft actuators based on a foamed silicone matrix with the working liquid (WL) captured in its pores that undergo the liquid–gas phase transition. For the first time, to gain the actuation strain of such composites, we added, to the WL, a substance that sublimates during the composite actuation. C1–C3 alcohols were tested as WLs, while the sublimation substance (SS) used was benzoic acid dissolved in the WL. It was found that the rejuvenation procedure is able to fill the composite pores with WL + SS solution. The effect of benzoic acid addition was revealed using the two-stage heating mode. The sublimation substance effectively extends the composite strain for methanol and ethanol as WL for about 20%. For C3 propanols, the strain is left nearly unchanged. In the open-air conditions, the high diffusion of WL + SS in silicone allows only a single actuation that makes it a disposable actuator, i.e., a kind of safety switch is proposed. The results obtained in this work pave the way to future, powerful multipurpose “soft safeties” appliances. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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19 pages, 13626 KB

Open AccessArticle

Advanced Thermal Protection Systems Enabled by Additive Manufacturing of Hybrid Thermoplastic Composites

by Teodor Adrian Badea, Alexa-Andreea Crisan and Lucia Raluca Maier

Polymers 2025, 17(22), 2974; https://doi.org/10.3390/polym17222974 - 7 Nov 2025

Cited by 1 | Viewed by 1267

Abstract

This study investigates seven advanced hybrid composite thermal protection system (TPS) prototypes, featuring an innovative internal air chamber design that reduces heat conduction and enhances overall thermal protection performance. Specimens were manufactured by fused deposition modeling (FDM), an additive manufacturing technique, using a [...] Read more.

This study investigates seven advanced hybrid composite thermal protection system (TPS) prototypes, featuring an innovative internal air chamber design that reduces heat conduction and enhances overall thermal protection performance. Specimens were manufactured by fused deposition modeling (FDM), an additive manufacturing technique, using a fire-retardant thermoplastic. Selected configurations were reinforced with continuous carbon or glass fibers, coated with ceramic surface layer, or hybridized with carbon fiber reinforced polymer (CFRP) layers or a CFRP laminate disk. To validate performance, a harsh oxy-acetylene torch (OAT) protocol was implemented, deliberately designed to exceed the severity of most reported typical ablative assessments. The exposed surface of each specimen was subjected to direct flame at a 50 mm distance, recording peak temperatures of 1600 ± 50 °C. Two samples of each configuration were tested under 60 and 90 s exposures. Back-face thermal readings at potential payload sites consistently remained below 85 °C, well under the 200 °C maximum standard threshold for TPS applications. Several configurations preserved structural integrity despite the extreme environment. Prototypes 4.1 and 4.2 demonstrate the most favorable performance, maintaining structural integrity and low back-face temperatures despite substantial thickness loss. By contrast, specimen 6.2 exhibited rapid degradation following 60 s of exposure, which served as a rigorous and selective early-stage screening tool for evaluating polymer-based ablative TPS architectures. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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25 pages, 4297 KB

Open AccessArticle

Application of Carbon–Silicon Hybrid Fillers Derived from Carbonised Rice Production Waste in Industrial Tread Rubber Compounds

by Valeryia V. Bobrova, Sergey V. Nechipurenko, Bayana B. Yermukhambetova, Andrei V. Kasperovich, Sergey A. Yefremov, Aigerim K. Kaiaidarova, Danelya N. Makhayeva, Galiya S. Irmukhametova, Gulzhakhan Zh. Yeligbayeva and Grigoriy A. Mun

Polymers 2025, 17(15), 2070; https://doi.org/10.3390/polym17152070 - 29 Jul 2025

Cited by 2 | Viewed by 1238

Abstract

The disposal of agro-industrial waste is a pressing environmental issue. At the same time, due to the high silica content in specific agricultural residues, their processed products can be utilised in various industrial sectors as substitutes for commercial materials. This study investigates the [...] Read more.

The disposal of agro-industrial waste is a pressing environmental issue. At the same time, due to the high silica content in specific agricultural residues, their processed products can be utilised in various industrial sectors as substitutes for commercial materials. This study investigates the key technological, physico-mechanical, and viscoelastic properties of industrial elastomeric compounds based on synthetic styrene–butadiene rubber, intended for the tread of summer passenger car tyres, when replacing the commercially used highly reinforcing silica filler (SF), Extrasil 150VD brand (white carbon black), with a carbon–silica filler (CSF). The CSF is produced by carbonising a finely ground mixture of rice production waste (rice husks and stems) in a pyrolysis furnace at 550–600 °C without oxygen. It was found that replacing 20 wt.pts. of silica filler with CSF in industrial tread formulations improves processing parameters (Mooney viscosity increases by up to 5.3%, optimal vulcanisation time by up to 9.2%), resistance to plastic deformation (by up to 7.7%), and tackiness of the rubber compounds (by 31.3–34.4%). Viscoelastic properties also improved: the loss modulus and mechanical loss tangent decreased by up to 24.0% and 14.3%, respectively; the rebound elasticity increased by up to 6.3% and fatigue resistance by up to 2.7 thousand cycles; and the internal temperature of samples decreased by 7 °C. However, a decrease in tensile strength (by 10.7–27.0%) and an increase in wear rate (up to 43.3% before and up to 22.5% after thermal ageing) were observed. Nevertheless, the overall results of this study indicate that the CSF derived from the carbonisation of rice production waste—containing both silica and carbon components—can effectively be used as a partial replacement for the commercially utilised reinforcing silica filler in the production of tread rubber for summer passenger car tyres. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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18 pages, 7614 KB

Open AccessArticle

The Influence of Print Orientation and Discontinuous Carbon Fiber Content on the Tensile Properties of Selective Laser-Sintered Polyamide 12

by Jonathan J. Slager, Joshua T. Green, Samuel D. Levine and Roger V. Gonzalez

Polymers 2025, 17(15), 2028; https://doi.org/10.3390/polym17152028 - 25 Jul 2025

Cited by 1 | Viewed by 1312

Abstract

Discontinuous fibers are commonly added to matrix materials in additive manufacturing to enhance properties, but such benefits may be constrained by print and fiber orientation. The additive processes of forming rasters and layers in powder bed fusion inherently cause anisotropy in printed parts. [...] Read more.

Discontinuous fibers are commonly added to matrix materials in additive manufacturing to enhance properties, but such benefits may be constrained by print and fiber orientation. The additive processes of forming rasters and layers in powder bed fusion inherently cause anisotropy in printed parts. Many print parameters, such as laser, temperature, and hatch pattern, influence the anisotropy of tensile properties. This study characterizes fiber orientation attributed to recoating non-encapsulated fibers and the resulting anisotropic tensile properties. Tensile and fracture properties of polyamide 12 reinforced with 0%, 2.5%, 5%, and 10% discontinuous carbon fibers by volume were characterized in two primary print/tensile loading orientations: tensile loading parallel to the recoater (“horizontal specimens”) and tensile load along the build axis (“vertical specimens”). Density and fractographic analysis indicate a homogeneous mixture with low porosity and primary fiber orientation along the recoating direction for both print orientations. Neat specimens (zero fiber) loaded in either direction have similar tensile properties. However, fiber-reinforced vertical specimens have significantly reduced consistency and tensile strength as fiber content increased, while the opposite is true for horizontal specimens. These datasets and results provide a mechanism to tune material properties and improve the functionality of selectively laser-sintered fiber-reinforced parts through print orientation selection. These datasets could be used to customize functionally graded parts with multi-material selective laser-sintering manufacturing. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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15 pages, 2112 KB

Open AccessArticle

Development of a Method for Blocking Polysodiumoxy(methyl)siloxane Obtained in an Alcohol Medium

by Marina A. Obrezkova, Alina A. Nesterkina and Aziz M. Muzafarov

Polymers 2025, 17(15), 2023; https://doi.org/10.3390/polym17152023 - 24 Jul 2025

Viewed by 763

Abstract

Polysodiumoxy(methyl)siloxane is a highly functional polymer matrix that can be used for the preparation of both functional and non-functional polymers, including molecular brushes. To determine the molecular weight parameters of the matrix, as well as its chemical structure, it is necessary to develop [...] Read more.

Polysodiumoxy(methyl)siloxane is a highly functional polymer matrix that can be used for the preparation of both functional and non-functional polymers, including molecular brushes. To determine the molecular weight parameters of the matrix, as well as its chemical structure, it is necessary to develop an effective method of blocking functional (in our case, sodiumoxy) groups due to their high reactivity. At the same time, the blocking product should represent a complete non-functionalized replica of polysodiumoxy(methyl)siloxane. Since the obtained polysodiumoxy(methyl)siloxane can contain both sodium- and hydroxy groups in its composition, the presence of both types of functional groups should be considered in the blocking process. In this work, we investigated the blocking process of polysodiumoxy(methyl)siloxane and the influence of blocking conditions on the blocked product. We carried out several variants of blocking, which differed in the order and method of introduction of reagents, as well as in the temperature regime. The chemical structure and molecular weight characteristics of the obtained polymers were analyzed by ¹H NMR spectroscopy and gel permeation chromatography (GPC), respectively. According to the blocking results, only in one case, complete non-functionalized replicas of polysodiumoxy(methyl)siloxane were obtained, which allows this technique to be used as a tool for the analysis of complex, highly functionalized organosilicon systems. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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20 pages, 9762 KB

Open AccessArticle

Wet Chemical-Synthesized Low-Loss Dielectric Composite Material Based on CuCl-Cu₇S₄ Nanoparticles and PVDF Copolymer

by Alexander A. Maltsev, Andrey A. Vodyashkin, Evgenia L. Buryanskaya, Olga Yu. Koval, Alexander V. Syuy, Sergei B. Bibikov, Irina E. Maltseva, Bogdan A. Parshin, Anastasia M. Stoynova, Pavel A. Mikhalev and Mstislav O. Makeev

Polymers 2025, 17(13), 1845; https://doi.org/10.3390/polym17131845 - 30 Jun 2025

Viewed by 1117

Abstract

Polymer composites with high dielectric permittivity (>10) and low dielectric loss are critical for energy storage and microelectronic applications. This study reports on a semi-transparent composite of a PVDF copolymer filled with Cu₇S₄ nanoparticles synthesized via a wet chemical route. [...] Read more.

Polymer composites with high dielectric permittivity (>10) and low dielectric loss are critical for energy storage and microelectronic applications. This study reports on a semi-transparent composite of a PVDF copolymer filled with Cu₇S₄ nanoparticles synthesized via a wet chemical route. Only a small content (6%) of copper sulfide increases the dielectric permittivity of the material from 10.4 to 15.9 (1 kHz), maintaining a low dielectric loss coefficient (less than 0.1). The incorporated nanoparticles affect the morphology of the composite film surface and crystalline phases in the whole volume, which was studied with FTIR spectroscopy, differential scanning calorimetry and scanning probe microscopy. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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24 pages, 12029 KB

Open AccessArticle

The Influence of Fillers on the Reinforcement Capabilities of Polypropylene Based Mono-Material and Core-Shell Fibers in Concrete, a Comparison

by Jonas Herz, Dirk Muscat and Nicole Strübbe

Polymers 2025, 17(13), 1781; https://doi.org/10.3390/polym17131781 - 27 Jun 2025

Viewed by 987

Abstract

Noncorrosive concrete reinforcement, such as polymer fibers, is needed to overcome the current issues caused by corroded steel reinforcements. Fibers made of polypropylene show a low bonding behavior in concrete. Fillers can help to overcome this issue but often lead to reduced mechanical [...] Read more.

Noncorrosive concrete reinforcement, such as polymer fibers, is needed to overcome the current issues caused by corroded steel reinforcements. Fibers made of polypropylene show a low bonding behavior in concrete. Fillers can help to overcome this issue but often lead to reduced mechanical properties. Core-shell fibers, which split the mechanical properties and the bonding behavior between the core and the shell component, could be a solution. This study investigates mono-material and core-shell fibers produced with calcium carbonate and bentonite fillers and compares their behavior in tensile tests, density measurements, contact angle measurements, topography measurements, single fiber pull-out tests, reflected light microscopy, and thermogravimetric analysis. The fillers caused an increased drawability, resulting in higher mechanical properties. Further, in the core-shell fibers, the calcium carbonate increased the surface roughness, which led to a better anchoring of the fiber in concrete, which was also visible in the deformation during pull-out observed in reflected light microscopy pictures. The thermogravimetric analysis showed a delay in onset of degradation for fibers containing bentonite. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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17 pages, 4185 KB

Open AccessArticle

Preparation of Microcellular High-Density Polyethylene with Thermal Expandable Microspheres

by Guo-Shun Chen, Xue-Kun Li and Wei-Cheng Yang

Polymers 2025, 17(13), 1773; https://doi.org/10.3390/polym17131773 - 26 Jun 2025

Cited by 1 | Viewed by 1123

Abstract

The microstructure and mechanical properties of foamed high-density polyethylene (HDPE) prepared with thermal expandable microspheres (TEMs) by an injection molding method were investigated, especially for the effect of different injection times, nozzle temperatures, and TEM contents. The results showed that it was beneficial [...] Read more.

The microstructure and mechanical properties of foamed high-density polyethylene (HDPE) prepared with thermal expandable microspheres (TEMs) by an injection molding method were investigated, especially for the effect of different injection times, nozzle temperatures, and TEM contents. The results showed that it was beneficial to increase the expansion ratio in the HDPE of microspheres with a shorter injection time and higher nozzle temperature. However, the addition of TEMs reduced the crystallinity of the foamed HDPE, and the crystallinity decreases further with the increasing TEMs content, which led to the decrease in Young’s modulus and tensile strength. When the nozzle temperature reached 220 °C, the mechanical properties of the foamed HDPE diminished significantly due to the collapse of the internal cells. At the TEMs content of 1.5 wt.%, an injection time of 2.0 s, and a nozzle temperature of 210 °C, a foamed HDPE was prepared with a cell size of 89.72 μm and a cell density of 4.39 × 10⁸ cells/cm³. This foam exhibited a reduction density of 5.75%, a tensile strength of 22.6 MPa, and a Yang’s modulus of 1172.3 MPa, demonstrating excellent overall mechanical properties. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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22 pages, 6784 KB

Open AccessArticle

Synergistic Effects of Hybrid Bio-Fillers and Modified Natural Rubber on Natural Rubber Composite Properties

by Supharat Inphonlek, Namthip Bureewong, Supawat Kotchapradit, Yupaporn Ruksakulpiwat and Chaiwat Ruksakulpiwat

Polymers 2025, 17(5), 632; https://doi.org/10.3390/polym17050632 - 26 Feb 2025

Cited by 11 | Viewed by 3253

Abstract

This work aims to investigate the synergistic effects of hybrid bio-fillers and compatibilizers on the properties of natural rubber composites. Rice husk silica (RSi) and hydroxyapatite (HA), derived from rice husk ash and seabass fish scales, respectively, were successfully prepared and used as [...] Read more.

This work aims to investigate the synergistic effects of hybrid bio-fillers and compatibilizers on the properties of natural rubber composites. Rice husk silica (RSi) and hydroxyapatite (HA), derived from rice husk ash and seabass fish scales, respectively, were successfully prepared and used as bio-fillers. Poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber (gDPNR) was synthesized via emulsion graft copolymerization, achieving a grafting efficiency and grafting percentage of 15.94 and 4.23%, respectively. The gDPNR was utilized as a compatibilizer in the preparation of natural rubber composites. The addition of hybrid bio-fillers at an RSi-to-HA ratio of 25:75 exhibited superior mechanical properties compared to composites containing a single filler. The incorporation of gDPNR improved filler dispersion and interfacial adhesion between the NR matrix and the bio-fillers, further enhancing the mechanical, thermal, and dielectric properties. The composite with hybrid bio-fillers and 10 phr of gDPNR exhibited the highest tensile strength, showing a 2.10-fold and 1.06-fold improvement over neat natural rubber composite and hybrid filler composite without compatibilizer, respectively. The presence of polar functional groups in gDPNR enhanced the dielectric constant of the natural rubber composites. These composites could have potential in sustainable industrial applications, including flexible electronics and eco-friendly devices. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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22 pages, 4503 KB

Open AccessArticle

Study of Adhesion–Cohesive Interactions of Modified Bitumen Compositions

by Antonina Dyuryagina, Alyona Degert, Yuliya Byzova, Kirill Ostrovnoy, Alexandr Demyanenko, Aida Lutsenko and Tatyana Shirina

Polymers 2025, 17(2), 199; https://doi.org/10.3390/polym17020199 - 14 Jan 2025

Cited by 2 | Viewed by 1486

Abstract

The aim of the work was to study the effect of additive concentration on changes in the adhesive and cohesive strength of bitumen. To evaluate the effectiveness of modifiers in the composition of binary and triple bitumen systems in relation to mineral fillers [...] Read more.

The aim of the work was to study the effect of additive concentration on changes in the adhesive and cohesive strength of bitumen. To evaluate the effectiveness of modifiers in the composition of binary and triple bitumen systems in relation to mineral fillers of two grades, the method of determination of the adhesive efficiency and thermodynamic calculations of adhesion and cohesion work were used. The following compounds were used as additives: AS-2 synthesized from the oil refining waste and AG-4I (waste sealing liquid). Adhesion–cohesion processes in modified bitumen systems are limited by the wetting effect of crushed stone and the intensity of intermolecular forces in the condensed phase of the binder. In the binary compositions, the addition of modifiers into bitumen significantly improves the cohesive strength and adhesive efficiency in relation to crushed stone. The introduction of AS-2 into bitumen compositions with AG-4I increases adhesion efficiency and thermodynamic work of adhesion in relation to the filler surface. The adhesion efficiency and thermodynamic work of adhesion in the “bitumen-AG-4I-AS-2” system reach their maximum at C_AG-4I = 3.0 g/dm³ and C_AS-2 = 1.5 g/dm³. In these concentration modes, the composition ensures maximum increase in adhesion efficiency (A_KS = 65.18%; A_KA = 48.11%) and the greatest increase in thermodynamic work of adhesion (W_A(KS) = 15.79 mN/m; W_A(KA) = 14.13 mN/m). Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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16 pages, 3138 KB

Open AccessArticle

Liquid–Gas Phase Transition Actuator: Rejuvenation Procedure Extended and Open-Air Performance

by Igor Bezsudnov, Alina Khmelnitskaia, Aleksandra Kalinina, Kristina Monakhova and Sergey Ponomarenko

Polymers 2025, 17(1), 20; https://doi.org/10.3390/polym17010020 - 25 Dec 2024

Cited by 3 | Viewed by 1307

Abstract

To achieve the actuation of silicone-based foamed composites, a liquid–gas phase transition of the liquid captured in its pores is employed. The uncertainty of key parameters for a single or sequential open-air performance of such soft actuators limits their application. To define the [...] Read more.

To achieve the actuation of silicone-based foamed composites, a liquid–gas phase transition of the liquid captured in its pores is employed. The uncertainty of key parameters for a single or sequential open-air performance of such soft actuators limits their application. To define the main characteristics of the composites, in this work, two functions of the liquid there were separated: the pore-forming agent (FPA) and working liquid (WL). It was demonstrated that the composites can be fabricated using either ethanol or methanol as the PFA, while any of the C1-C4 alcohols can be used as the WL. The results of the sequential actuation tests of the composites revealed that pore formation depends on the composite viscosity during curation, while their expansion in single heat experiments can be approximated by a unified linear relation. Based on a Mendeleev–Clapeyron equation, the qualitative model for predicting the actuator strain is proposed. It was found that the composites with C3–C4 alcohols as the WL outperform ethanol-containing composites on the number of cycles survived under open-air conditions. These findings pave the way to control the operation of soft actuators by manipulating WL variation and PFA content during the composite cure to set the operation temperature and degree of expansion of pre-formed actuators. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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22 pages, 7824 KB

Open AccessArticle

The Stability Evaluation of Ceria Slurry Using Polymer Dispersants with Varying Contents for Chemical Mechanical Polishing Process

by Sohee Hwang, Jihee Park and Woonjung Kim

Polymers 2024, 16(24), 3593; https://doi.org/10.3390/polym16243593 - 22 Dec 2024

Cited by 6 | Viewed by 4615

Abstract

The chemical mechanical polishing/planarization (CMP) is essential for achieving the desired surface quality and planarity required for subsequent layers and processing steps. However, the aggregation of slurry particles caused by abrasive materials can lead to scratches, defects, increased surface roughness, degradation the quality [...] Read more.

The chemical mechanical polishing/planarization (CMP) is essential for achieving the desired surface quality and planarity required for subsequent layers and processing steps. However, the aggregation of slurry particles caused by abrasive materials can lead to scratches, defects, increased surface roughness, degradation the quality and durability of the finished surface after milling processes during the CMP process. In this study, ceria slurry was prepared using polymer dispersant with zinc salt of ethylene acrylic acid (EAA) copolymer at different contents of 5, 6, and 7 wt% (denoted as D5, D6, and D7) to minimize particle aggregation commonly observed in CMP slurries. Among them, the D7 sample exhibited smaller particle sizes compared to commercial ceria slurry, which was attributed to the influence of the carboxyl groups (-COOH) of the polyacrylic acid polymer coating the ceria particles. It is believed that the polymer dispersant more effectively adsorbs onto the particle surfaces, increasing electrostatic repulsion between particles and thereby reducing particle size. Furthermore, the stability of the prepared slurry was evaluated under extreme conditions over three months at 25 °C (both open and closed conditions), 4 °C, and 60 °C. The D7 slurry remained stable with no significant changes observed. In addition, the prepared D7 ceria slurry exhibited a slightly higher removal rate (RR) and better uniformity, which can be attributed to the smaller particle sizes of the ceria nanoparticles compared to those in the commercial slurry. This suggests that the colloidal stability of the D7 ceria slurry is superior to that of the commercial ceria slurry. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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14 pages, 7727 KB

Open AccessArticle

Polymer Matrix Nanocomposites Fabricated with Copper Nanoparticles and Photopolymer Resin via Vat Photopolymerization Additive Manufacturing

by Leon D. Gil, Sergio Neves Monteiro and Henry A. Colorado

Polymers 2024, 16(17), 2434; https://doi.org/10.3390/polym16172434 - 28 Aug 2024

Cited by 9 | Viewed by 2632

Abstract

This investigation explores the fabrication of polymer matrix nanocomposites via additive manufacturing (AM), using a UV photopolymerization resin and copper nanoparticles (Cu-NPs) with vat photopolymerization 3D printing technology. The aim in this study is to investigate the mentioned materials in different formulations in [...] Read more.

This investigation explores the fabrication of polymer matrix nanocomposites via additive manufacturing (AM), using a UV photopolymerization resin and copper nanoparticles (Cu-NPs) with vat photopolymerization 3D printing technology. The aim in this study is to investigate the mentioned materials in different formulations in terms of inexpensive processing, the property related variability, and targeting multifunctional applications. After the AM process, samples were post-cured with UV light in order to obtain better mechanical properties. The particles and resin were mixed using an ultrasonicator, and the particle contents used were 0.0, 0.5, and 1.0 wt %. The process used in this investigation was simple and inexpensive, as the technologies used are quite accessible, from the 3D printer to the UV curing device. These formulations were characterized with scanning electron microscopy (SEM) to observe the materials’ microstructure and tensile tests to quantify stress–strain derived properties. Results showed that, besides the simplicity of the process, the mixing was effective, which was observed in the scanning electron microscope. Additionally, the tensile strength was increased with the UV irradiation exposure, while the strain properties did not change significantly. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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15 pages, 13986 KB

Open AccessArticle

Preparation of Polydopamine Functionalized HNIW Crystals and Application in Solid Propellants

by Fengdan Zhu, Chang Liu, Desheng Yang and Guoping Li

Polymers 2024, 16(11), 1566; https://doi.org/10.3390/polym16111566 - 1 Jun 2024

Cited by 2 | Viewed by 1984

Abstract

The application of hexanitrohexaazaisowurtzitane (HNIW) as an oxidizer in solid propellants aligns with the pursuit of high-energy materials. However, the phase transformation behavior and high impact sensitivity of HNIW are its limitations. Due to the strong adhesion and mild synthesis conditions, polydopamine (PDA) [...] Read more.

The application of hexanitrohexaazaisowurtzitane (HNIW) as an oxidizer in solid propellants aligns with the pursuit of high-energy materials. However, the phase transformation behavior and high impact sensitivity of HNIW are its limitations. Due to the strong adhesion and mild synthesis conditions, polydopamine (PDA) has been employed to modify HNIW. However, the method suffers from a slow coating process and a non-ideal coating effect under short reaction time. Herein, oxygen-accelerated dopamine in situ polymerization coating method was developed. It was found that oxygen not only reduced the coating time but also contributed to forming a dense and uniform PDA layer. HNIW@PDA coated in oxygen for 6 h exhibited the most favorable performance, with a delay of 20.8 °C in the phase transition temperature and a reduction of 145.45% in the impact sensitivity. The -OH groups on the surface of PDA enhanced the interaction between HNIW and polymer binders, resulting in a 20.36% reduction in the dewetting percentage. The lower content of PDA in HNIW@PDA (1.17%) resulted in minimal variation in the heat of explosion for HNIW@PDA-based HTPB propellant (6287 kJ/kg) in comparison to HNIW-based HTPB propellant (6297 kJ/kg). Hence, HNIW@PDA-based propellants are expected to offer an alternative with promising safety and mechanical performance compared to existing HNIW-based propellants, thus facilitating the application of HNIW in high-energy propellants. This work presents a low-cost method for efficiently inhibiting the phase transformation of polycrystalline explosives and reducing the impact sensitivity. It also offers a potential approach to enhance the interfacial interaction between nitro-containing explosives and polymer binders. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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19 pages, 6494 KB

Open AccessArticle

Comparative Investigation of Nano-Sized Silica and Micrometer-Sized Calcium Carbonate on Structure and Properties of Natural Rubber Composites

by Nabil Hayeemasae, Siriwat Soontaranon and Abdulhakim Masa

Polymers 2024, 16(8), 1051; https://doi.org/10.3390/polym16081051 - 11 Apr 2024

Cited by 15 | Viewed by 2827

Abstract

Fillers have been widely used in natural rubber (NR) products. They are introduced to serve as a strategy for modifying the final properties of NR vulcanizates. Silica and calcium carbonate (CaCO₃) are among the fillers of choice when the color of [...] Read more.

Fillers have been widely used in natural rubber (NR) products. They are introduced to serve as a strategy for modifying the final properties of NR vulcanizates. Silica and calcium carbonate (CaCO₃) are among the fillers of choice when the color of the products is concerned. In this case, a special focus was to compare the vulcanizing efficiency of NR filled with two different filler types, namely nano-sized silica and micrometer-sized CaCO₃. This study focused on the effects of the loading level (10–50 parts per hundred parts of rubber, phr) on the final properties and structural changes of NR composites. The results indicated that increased filler loading led to higher curing torques and stiffness of the rubber composites irrespective of the type of filler used. The better filler dispersion was achieved in composites filled with CaCO₃ which is responsible for less polarity of CaCO₃ compared to silica. Good filler distribution enhanced filler–matrix interactions, improving swelling resistance and total crosslink density, and delaying stress relaxation. The modulus and tensile strength of both composites also improved over the content of fillers. The CaCO₃-filled composites reached their maximum tensile strength at 40 phr, exceeding, by roughly 88%, the strength of an unfilled sample. Conversely, the maximum tensile strength of silica-filled NR was at 20 phr and was only slightly higher than that of its unfilled counterpart. This discrepancy was ascribed to the stronger rubber–filler interactions in cases with CaCO₃ filler. Effective rubber–filler interactions improved strain-induced crystallization, increasing crystallinity during stretching and reducing the strain at which crystallization begins. In contrast, large silica aggregates with poor dispersion reduced the overall crosslink density, and degraded the thermomechanical properties, tensile properties, and strain-induced crystallization ability of the NR. The results clearly indicate that CaCO₃ should be favored over silica as a filler in the production of some rubber products where high performance was not the main characteristic. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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15 pages, 4588 KB

Open AccessArticle

Modification of Polyethylene Glycol-Hydroxypropyl Methacrylate Polymeric Micelles Loaded with Curcumin for Cellular Internalization and Cytotoxicity to Wilms Tumor 1-Expressing Myeloblastic Leukemia K562 Cells

by Siriporn Okonogi, Chuda Chittasupho, Tanongsak Sassa-deepaeng, Nattakanwadee Khumpirapang and Songyot Anuchpreeda

Polymers 2024, 16(7), 917; https://doi.org/10.3390/polym16070917 - 27 Mar 2024

Cited by 2 | Viewed by 2295

Abstract

Curcumin loaded in micelles of block copolymers of ω-methoxypoly(ethylene glycol) and N-(2-hydroxypropyl) methacrylamide modified with aliphatic dilactate (CD) or aromatic benzoyl group (CN) were previously reported to inhibit human ovarian carcinoma (OVCAR-3), human colorectal adenocarcinoma (Caco-2), and human lymphoblastic leukemia (Molt-4) cells. Myeloblastic [...] Read more.

Curcumin loaded in micelles of block copolymers of ω-methoxypoly(ethylene glycol) and N-(2-hydroxypropyl) methacrylamide modified with aliphatic dilactate (CD) or aromatic benzoyl group (CN) were previously reported to inhibit human ovarian carcinoma (OVCAR-3), human colorectal adenocarcinoma (Caco-2), and human lymphoblastic leukemia (Molt-4) cells. Myeloblastic leukemia cells (K562) are prone to drug resistance and differ in both cancer genotype and phenotype from the three mentioned cancer cells. In the present study, CD and CN micelles were prepared and their effects on K562 and normal cells were explored. The obtained CD and CN showed a narrow size distribution with diameters of 63 ± 3 and 50 ± 1 nm, respectively. The curcumin entrapment efficiency of CD and CN was similarly high, above 80% (84 ± 8% and 91 ± 3%). Both CD and CN showed suppression on WT1-expressing K562 and high cell-cycle arrest at the G2/M phase. However, CD showed significantly higher cytotoxicity to K562, with faster cellular uptake and internalization than CN. In addition, CD showed better compatibility with normal red blood cells and peripheral blood mononuclear cells than CN. The promising CD will be further investigated in rodents and possibly in clinical studies for leukemia treatment. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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13 pages, 564 KB

Open AccessArticle

Mechanical Testing of Selective-Laser-Sintered Polyamide PA2200 Details: Analysis of Tensile Properties via Finite Element Method and Machine Learning Approaches

by Ivan Malashin, Dmitriy Martysyuk, Vadim Tynchenko, Vladimir Nelyub, Aleksei Borodulin and Andrey Galinovsky

Polymers 2024, 16(6), 737; https://doi.org/10.3390/polym16060737 - 8 Mar 2024

Cited by 11 | Viewed by 2860

Abstract

This study delves into the mechanical characteristics of polyamide PA2200 components crafted using selective laser sintering (SLS) technology. Our primary objective is to analyze the tensile behavior of the components printed at various orientations, showing its response to diverse loading conditions. Finite element [...] Read more.

This study delves into the mechanical characteristics of polyamide PA2200 components crafted using selective laser sintering (SLS) technology. Our primary objective is to analyze the tensile behavior of the components printed at various orientations, showing its response to diverse loading conditions. Finite element method (FEM) modeling was employed to analyze the tensile behavior of these details. The time determined for breaking the detail is 9 s. In addition we forecast key properties, such as tensile behavior and strength, using machine learning (ML) techniques, and the best models are for predicting relative elongation are KNeighborsRegressor and SVR. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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21 pages, 6998 KB

Open AccessArticle

Mouldable Conductive Plastic with Optimised Mechanical Properties

by Arfat Anis, Abdullah Alhamidi, Zahir Bashir, Mohammad Asif Alam and Saeed M. Al-Zahrani

Polymers 2024, 16(3), 311; https://doi.org/10.3390/polym16030311 - 23 Jan 2024

Cited by 3 | Viewed by 2553

Abstract

This paper investigates making an injection mouldable conductive plastic formulation that aims for conductivity into the electromagnetic interference (EMI) shielding range, with good mechanical properties (i.e., stiffness, strength, and impact resistance). While conductivity in the range (electrostatic charge dissipation) and EMI shielding have [...] Read more.

This paper investigates making an injection mouldable conductive plastic formulation that aims for conductivity into the electromagnetic interference (EMI) shielding range, with good mechanical properties (i.e., stiffness, strength, and impact resistance). While conductivity in the range (electrostatic charge dissipation) and EMI shielding have been attained by incorporating conductive fillers such as carbon black, metals powders, and new materials, such as carbon nanotubes (CNTs), this often occurs with a drop in tensile strength, elongation-to-break resistance, and impact resistance. It is most often the case that the incorporation of high modulus fillers leads to an increase in modulus but a drop in strength and impact resistance. In this work, we have used short carbon fibres as the conductive filler and selected a 50/50 PBT/rPET (recycled PET) for the plastic matrix. Carbon fibres are cheaper than CNTs and graphenes. The PBT/rPET has low melt viscosity and crystallises sufficiently fast during injection moulding. To improve impact resistance, a styrene-ethylene-butadiene-styrene (SEBS) rubber toughening agent was added to the plastic. The PBT/rPET had very low-impact resistance and the SEBS provided rubber toughening to it; however, the rubber caused a drop in the tensile modulus and strength. The short carbon fibre restored the modulus and strength, which reached higher value than the PBT/rPET while providing the conductivity. Scanning electron microscope pictures showed quite good bonding of the current filler (CF) to the PBT/rPET. An injection mouldable conductive plastic with high conductivity and raised modulus, strength, and impact resistance could be made. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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17 pages, 2731 KB

Open AccessArticle

Synthesis of Vinyl-Containing Polydimethylsiloxane in An Active Medium

by Alina G. Khmelnitskaia, Aleksandra A. Kalinina, Ivan B. Meshkov, Rinat S. Tukhvatshin, Georgii V. Cherkaev, Sergey A. Ponomarenko and Aziz M. Muzafarov

Polymers 2024, 16(2), 257; https://doi.org/10.3390/polym16020257 - 16 Jan 2024

Cited by 3 | Viewed by 4760

Abstract

This research deals with the synthesis of copoly(methylvinyl)(dimethyl)siloxanes by the copolycondensation of dimethyldiethoxy- and methylvinyldimethoxysilane in an active medium, followed by thermal condensation in a vacuum. We achieved a range of copolymers exhibiting finely tuned molecular weights spanning between 1500 and 20,000 with [...] Read more.

This research deals with the synthesis of copoly(methylvinyl)(dimethyl)siloxanes by the copolycondensation of dimethyldiethoxy- and methylvinyldimethoxysilane in an active medium, followed by thermal condensation in a vacuum. We achieved a range of copolymers exhibiting finely tuned molecular weights spanning between 1500 and 20,000 with regulated functional methylvinylsiloxane units. Analysis of the microstructure showed that the copolymerization predominantly formed products demonstrating a random distribution of units (R~1). However, an increase in the content of vinyl-containing monomers increases the R parameter, indicating an enhanced tendency towards alternating linkages within the copolymer matrix. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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12 pages, 2321 KB

Open AccessArticle

Enhanced Mechanical Properties of PVA Hydrogel by Low-Temperature Segment Self-Assembly vs. Freeze–Thaw Cycles

by Fei Wu, Jianfeng Gao, Yang Xiang and Jianming Yang

Polymers 2023, 15(18), 3782; https://doi.org/10.3390/polym15183782 - 15 Sep 2023

Cited by 49 | Viewed by 9207

Abstract

The rapid and effective fabrication of polyvinyl alcohol (PVA) hydrogels with good mechanical properties is of great significance yet remains a huge challenge. The preparation of PVA hydrogels via the conventional cyclic freeze–thaw method is intricate and time-intensive. In this study, a pioneering [...] Read more.

The rapid and effective fabrication of polyvinyl alcohol (PVA) hydrogels with good mechanical properties is of great significance yet remains a huge challenge. The preparation of PVA hydrogels via the conventional cyclic freeze–thaw method is intricate and time-intensive. In this study, a pioneering approach involving the utilization of low-temperature continuous freezing is introduced to produce a novel PVA-ethylene glycol (EG) gel. Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM) confirm that with the assistance of EG, PVA molecular chains can self-assemble to generate an abundance of microcrystalline domains at low temperatures, thus improving the mechanical properties of PVA-EG gel. Remarkably, when the mass ratio of H₂O/EG is 4:6, the gel’s maximum tensile strength can reach 2.5 MPa, which is much higher than that of PVA gels prepared via the freeze–thaw method. The preparation process of PVA-EG gel is simple, and its properties are excellent, which will promote the wide application of PVA tough gel in many fields. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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17 pages, 41014 KB

Open AccessArticle

Enhanced Antioxidant Activity and Reduced Cytotoxicity of Silver Nanoparticles Stabilized by Different Humic Materials

by Maria V. Zykova, Alexander B. Volikov, Evgeny E. Buyko, Kristina A. Bratishko, Vladimir V. Ivanov, Andrey I. Konstantinov, Lyudmila A. Logvinova, Dmitrii A. Mihalyov, Nikita A. Sobolev, Anastasia M. Zhirkova, Sergey V. Maksimov, Irina V. Perminova and Mikhail V. Belousov

Polymers 2023, 15(16), 3386; https://doi.org/10.3390/polym15163386 - 12 Aug 2023

Cited by 18 | Viewed by 3176

Abstract

The current article describes the biological activity of new biomaterials combining the “green” properties of humic substances (HSs) and silver nanoparticles. The aim is to investigate the antioxidant activity (AOA) of HS matrices (macroligands) and AgNPs stabilized with humic macroligands (HS-AgNPs). The unique [...] Read more.

The current article describes the biological activity of new biomaterials combining the “green” properties of humic substances (HSs) and silver nanoparticles. The aim is to investigate the antioxidant activity (AOA) of HS matrices (macroligands) and AgNPs stabilized with humic macroligands (HS-AgNPs). The unique chemical feature of HSs makes them very promising ligands (matrices) for AgNP stabilization. HSs have previously been shown to exert many pharmacological effects mediated by their AOA. AgNPs stabilized with HS showed a pronounced ability to bind to reactive oxygen species (ROS) in the test with ABTS. Also, higher AOA was observed for HS-AgNPs as compared to the HS matrices. In vitro cytotoxicity studies have shown that the stabilization of AgNPs with the HS matrices reduces the cytotoxicity of AgNPs. As a result of in vitro experiments with the use of 2,7-dichlorodihydrofluorescein diacetate (DCFDA), it was found that all HS materials tested and the HS-AgNPs did not exhibit prooxidant effects. Moreover, more pronounced AOA was shown for HS-AgNP samples as compared to the original HS matrices. Two putative mechanisms of the pronounced AOA of the tested compositions are proposed: firstly, the pronounced ability of HSs to inactivate ROS and, secondly, the large surface area and surface-to-volume ratio of HS-AgNPs, which facilitate electron transfer and mitigate kinetic barriers to the reduction reaction. As a result, the antioxidant properties of the tested HS-AgNPs might be of particular interest for biomedical applications aimed at inhibiting the growth of bacteria and viruses and the healing of purulent wounds. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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26 pages, 22547 KB

Open AccessArticle

Thioether-Containing Zirconium(Alkoxy)Siloxanes: Synthesis and Study of Dielectric and Mechanical Properties of Silica-Filled Polydimethylsiloxane Compositions Cured by Them

by Alexander N. Tarasenkov, Maria S. Parshina, Galina P. Goncharuk, Kirill M. Borisov, Evgeniy K. Golubev, Ivan B. Meshkov, Georgiy V. Cherkaev, Vitaliy G. Shevchenko, Sergey A. Ponomarenko and Aziz M. Muzafarov

Polymers 2023, 15(16), 3361; https://doi.org/10.3390/polym15163361 - 10 Aug 2023

Cited by 3 | Viewed by 2040

Abstract

A number of thioether-containing zirconium siloxanes, differing in their composition and metal atom shielding degree with a siloxy substituent, were synthesized and characterized. Synthesis of such compounds made it possible to evaluate the effect of sulfur atoms’ presence in the cured compositions on [...] Read more.

A number of thioether-containing zirconium siloxanes, differing in their composition and metal atom shielding degree with a siloxy substituent, were synthesized and characterized. Synthesis of such compounds made it possible to evaluate the effect of sulfur atoms’ presence in the cured compositions on their dielectric properties, as well as to evaluate their curing ability and influence on mechanical characteristics compared to the sulfur-free analogs obtained earlier. Studying a wide range of compositions differing in their content and ratio of metallosiloxane and silica components revealed that such systems are still typical dielectrics. At the same time, the introduction of thioether groups can provide increased dielectric constant and conductivity in comparison with previously obtained sulfur-free similar compositions in the <10² Hz frequency range (dielectric constant up to ~10–30 at frequency range 1–10 Hz). As before, the dielectric parameters increase is directly determined by the silica component proportion in the cured material. It is also shown that varying sulfur-containing zirconium siloxanes structure and functionality and its combination with previously obtained sulfur–free analogs, along with varying the functionality and rubber chain length, can be an effective tool for changing the dielectric and mechanical material parameters in a wide range (tensile strength 0.5–7 Mpa, elastic deformation 2–300%), which determine the prospects for the use of such cured systems as dielectric elastomers for various purposes. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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45 pages, 6680 KB

Open AccessReview

Preparation and Research Progress of Polymer-Based Anion Exchange Chromatography Stationary Phases

by Haolin Liu, Jingwei Xu, Yifan Shen, Shi Cheng, Yangyang Sun, Chendong Shuang and Aimin Li

Polymers 2026, 18(3), 389; https://doi.org/10.3390/polym18030389 - 31 Jan 2026

Viewed by 1039

Abstract

Ion chromatography (IC) serves as a pivotal technique in trace ion analysis, and the separation performance of IC is largely determined by the properties of stationary phases. In contrast to silica-based matrices, polymer-based stationary phases have garnered significant interest owing to their outstanding [...] Read more.

Ion chromatography (IC) serves as a pivotal technique in trace ion analysis, and the separation performance of IC is largely determined by the properties of stationary phases. In contrast to silica-based matrices, polymer-based stationary phases have garnered significant interest owing to their outstanding pH stability and mechanical robustness. However, unmodified polymer matrices usually lack necessary ion exchange functions and selectivity; therefore, precise functional modification is the key to improving their chromatographic separation performance. This paper provides a systematic overview of recent advances in the synthesis and functional modification of polymer-based anion exchange chromatography stationary phases over the past few years. Firstly, the types and characteristics of polymer matrices commonly used for functional modification are summarized; secondly, the origin and improvement of common synthesis methods such as microporous membrane emulsification, droplet microfluidics, suspension polymerization, emulsion polymerization, soap-free emulsion polymerization, precipitation polymerization, dispersion polymerization, and seed swelling are introduced according to the molding methods of polymer matrices; furthermore, the principles, characteristics, and development status of mainstream functionalization strategies, including chemical derivatization, surface grafting, latex agglomeration, and hyperbranching, are emphasized. Finally, the existing challenges and prospective development trends in this field are discussed and outlooked, with the purpose of offering insights for the targeted design and practical application of high-performance polymer-based anion exchange chromatography stationary phases. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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13 pages, 4309 KB

Open AccessReview

Accuracy and Powder Removal Limits in Multi Jet Fusion 3D Printing

by Karel Raz, Zdenek Chval and Petra Faitova

Polymers 2025, 17(20), 2804; https://doi.org/10.3390/polym17202804 - 21 Oct 2025

Viewed by 1247

Abstract

Multi Jet Fusion (MJF) is a leading technology for producing functional polymer parts. However, it still faces challenges with dimensional accuracy and removing unfused powder from complex internal geometries. First, dimensional accuracy was mapped by producing 45 identical PA12 specimens on an HP [...] Read more.

Multi Jet Fusion (MJF) is a leading technology for producing functional polymer parts. However, it still faces challenges with dimensional accuracy and removing unfused powder from complex internal geometries. First, dimensional accuracy was mapped by producing 45 identical PA12 specimens on an HP MJF 4200 printer in a 5 × 9 layout across five vertical layers. The analysis revealed a consistent pattern: parts located in the central positions of the build volume exhibited the poorest accuracy, while those near the perimeter were the most precise, regardless of their vertical height. This spatial variation is attributed to non-uniform thermal control from the printer’s adaptive lamp–thermal camera system. Second, the limits of powder removal from closed body-centered cubic (BCC) lattice structures were quantified. Using sandblasting and X-ray inspection, a strong inverse relationship was found between a lattice’s relative density and the maximum thickness that could be thoroughly cleaned of powder. For example, low-density structures (ρ = 0.07) could be cleaned up to five layers deep, whereas high-density structures (ρ = 0.39–0.47) were limited to only 1.5–1.7 layers. These findings offer actionable guidelines for optimizing part placement and designing internal lattice structures for MJF technology. The key findings are the spatial variation in dimensional accuracy in MJF printing, where the central parts are the least accurate and perimeter parts are the most precise, and the inverse relationship between a lattice’s relative density (ρ) and cleanable thickness. Specifically, low-density structures (ρ = 0.07) could be thoroughly cleaned up to five layers, while high-density ones (ρ = 0.39–0.47) were limited to approximately 1.5–1.7 layers. The layer thickness was a pre-designed parameter (2, 3, 4, and 5 layers), and powder removal was supported by using automated sandblasting followed by verification via industrial X-ray imaging. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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28 pages, 2183 KB

Open AccessReview

Production Technologies and Application of Polymer Composites in Engineering: A Review

by Milan Bukvić, Saša Milojević, Sandra Gajević, Momčilo Đorđević and Blaža Stojanović

Polymers 2025, 17(16), 2187; https://doi.org/10.3390/polym17162187 - 9 Aug 2025

Cited by 39 | Viewed by 7099

Abstract

Composite materials have been increasingly used in various branches of industry, transport, construction, and medicine—as well as in other sectors of the economy and science—in recent decades. A significant advancement in the improvement of composite material characteristics has been achieved through the use [...] Read more.

Composite materials have been increasingly used in various branches of industry, transport, construction, and medicine—as well as in other sectors of the economy and science—in recent decades. A significant advancement in the improvement of composite material characteristics has been achieved through the use of nanoparticles, which substantially enhance the properties of the base material, whether it is the matrix or the reinforcing phase in hybrid composites. The broad application of polymers and polymer composites in many areas of engineering has had a significant impact on reducing friction and wear, improving the thermal characteristics of individual components and entire technical systems, enhancing electrical conductivity, reducing the specific weight of components, lowering noise and vibration levels, and ultimately decreasing fuel consumption, production costs, and the costs of operation and maintenance of technical systems. This paper explores the potential applications of polymer composites in various assemblies and components of conventional vehicles, as well as in hybrid and electric vehicles. Furthermore, their use in medicine and the defense industry is examined—fields in which some authors believe composites were first pioneered. Finally, aviation represents an indispensable domain for the application of such materials, presenting unique exploitation boundary conditions, including dynamic environmental changes such as variations in temperature, pressure, velocity, and direction, as well as the need for high levels of protection. Future research can be unequivocally focused on the structural and technological advancement of polymer composites, specifically through optimization aimed at reducing waste and lowering production costs. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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18 pages, 1023 KB

Open AccessReview

Chitosan Nanoparticle-Based Drug Delivery Systems: Advances, Challenges, and Future Perspectives

by Alina Stefanache, Ionut Iulian Lungu, Nicoleta Anton, Daniela Damir, Cristian Gutu, Iulia Olaru, Alina Plesea Condratovici, Madalina Duceac (Covrig), Marcu Constantin, Gabriela Calin, Letitia Doina Duceac and Monica Boev

Polymers 2025, 17(11), 1453; https://doi.org/10.3390/polym17111453 - 23 May 2025

Cited by 47 | Viewed by 10274

Abstract

The effectiveness and uses of chitosan nanoparticles (CNPs) in drug delivery systems are examined in this work. Important results include the improved drug encapsulating efficiency: CNPs showed up to 90% encapsulation for different therapeutic agents. Furthermore, the research shows that CNPs provide extended-release [...] Read more.

The effectiveness and uses of chitosan nanoparticles (CNPs) in drug delivery systems are examined in this work. Important results include the improved drug encapsulating efficiency: CNPs showed up to 90% encapsulation for different therapeutic agents. Furthermore, the research shows that CNPs provide extended-release patterns, greatly enhancing medication bioavailability especially for hydrophobic compounds. One interesting outcome was the greater drug stability in acidic surroundings, which are common in the stomach, where CNPs turn into a gel and later inflate in the intestine where the drug is released. Moreover, CNPs showed a 2–3-fold improvement in the absorption of encapsulated pharmaceuticals relative to traditional formulations, therefore indicating their capacity to overcome the problems of low oral bioavailability. These nanoparticles’ pH-sensitive character produced a 50–70% increase in drug release at certain pH values, hence maximizing therapeutic results. Significantly less systemic toxicity was seen in the in vivo tests, and at therapeutic dosages there were no noted side effects. Histological study confirmed the biocompatibility and non-toxicity of CNPs, therefore attesting their fit for long-term usage. These results highlight the great potential of CNPs in providing effective, focused, continuous drug release, hence improving therapeutic effectiveness and patient compliance. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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