Polymers

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13 pages, 4426 KiB

Open AccessArticle

Augmenting the Efficacy of a Polyvinyl Alcohol Selective Layer Coated on Polyvinylidene Fluoride Support Membranes with Kaolinite Introduction for Improved Pervaporation Dehydration of Epichlorohydrin/Isopropanol/Water Ternary Systems

by Shivshankar Chaudhari, YeWon Jeong, HyeonTae Shin, SeWook Jo, MinYoung Shon, SeungEun Nam and YouIn Park

Polymers 2024, 16(6), 835; https://doi.org/10.3390/polym16060835 - 18 Mar 2024

Viewed by 782

Abstract

Composite membranes with a polyvinyl alcohol (PVA) selective layer composed of well-dispersed hydrophilic kaolinite particles coated on a polyvinylidene fluoride (PVDF) support were developed. They were applied to the pervaporation dehydration of the industrially important epichlorohydrin (ECH)/isopropanol (IPA)/water ternary mixture. In comparison with [...] Read more.

Composite membranes with a polyvinyl alcohol (PVA) selective layer composed of well-dispersed hydrophilic kaolinite particles coated on a polyvinylidene fluoride (PVDF) support were developed. They were applied to the pervaporation dehydration of the industrially important epichlorohydrin (ECH)/isopropanol (IPA)/water ternary mixture. In comparison with raw kaolinite (RK), hydrophilic kaolinite (HK) enhanced the mechanical properties, hydrophilicity, and thermal stability of the PVA selective layer, as confirmed by universal testing, the contact angle, and TGA analyses, respectively. The pervaporation results revealed that the addition of HK particles significantly enhanced the separation factor (3-fold). Only a marginal reduction in flux was observed with ECH/IPA/water, 50/30/20 (w/w %) at 40 °C. An HK particle concentration of 4 wt.% with respect to PVA delivered the highest flux performance of 0.86 kg/m²h and achieved a separation factor of 116. The PVA–kaolinite composite membrane exhibited pronounced resistance to the ECH-containing feed, demonstrating a sustained flux and separation factor throughout an extended pervaporation stability test lasting 250 h. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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20 pages, 8955 KiB

Open AccessArticle

Tribological Behavior of Cotton Fabric/Phenolic Resin Laminated Composites Reinforced with Two-Dimensional Materials

by Yonggang Guo, Chenyang Fang, Tingmei Wang, Qihua Wang, Fuzhi Song and Chao Wang

Polymers 2023, 15(22), 4454; https://doi.org/10.3390/polym15224454 - 18 Nov 2023

Cited by 1 | Viewed by 1117

Abstract

In this study, cotton fabric-reinforced phenolic resin (CPF) composites were modified by adding four two-dimensional fillers: graphitic carbon nitride (g-C₃N₄), graphite (Gr), molybdenum disulfide (MoS₂), and hexagonal boron nitride (h-BN). The tribological properties of these modified materials [...] Read more.

In this study, cotton fabric-reinforced phenolic resin (CPF) composites were modified by adding four two-dimensional fillers: graphitic carbon nitride (g-C₃N₄), graphite (Gr), molybdenum disulfide (MoS₂), and hexagonal boron nitride (h-BN). The tribological properties of these modified materials were investigated under dry friction and water lubrication conditions. The CPF/Gr composite exhibits significantly better tribological performance than the other three filler-modified CPF composites under dry friction, with a 24% reduction in friction coefficient and a 78% reduction in wear rate compared to the unmodified CPF composite. Under water lubrication conditions, all four fillers did not significantly alter the friction coefficient of the CPF composites. However, except for an excessive amount of Gr, the other three fillers can reduce the wear rate. Particularly in the case of 10% MoS₂ content, the wear rate decreased by 56%. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed for the analysis of the morphology and composition of the transfer films. Additionally, molecular dynamics (MD) simulations were conducted to investigate the adsorption effects of CPF/Gr and CPF/MoS₂ composites on the counterpart surface under both dry friction and water lubrication conditions. The difference in the adsorption capacity of CPF/Gr and CPF/MoS₂ composites on the counterpart, as well as the resulting formation of transfer films, accounts for the variation in tribological behavior between CPF/Gr and CPF/MoS₂ composites. By combining the lubrication properties of MoS₂ and Gr under dry friction and water lubrication conditions and using them as co-fillers, we can achieve a synergistic lubrication effect. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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18 pages, 10794 KiB

Open AccessArticle

Enhancing Textile Water Repellency with Octadecyltrichlorosilane (OTS) and Hollow Silica Nanoparticles

by Mahshab Sheraz, Byul Choi and Juran Kim

Polymers 2023, 15(20), 4065; https://doi.org/10.3390/polym15204065 - 12 Oct 2023

Viewed by 1324

Abstract

Superhydrophobic coatings have attracted substantial attention owing to their potential application in various industries. Conventional textiles used in daily life are prone to staining with water and household liquids, necessitating the development of water-repellent and stain-resistant coatings. In this study, we fabricated a [...] Read more.

Superhydrophobic coatings have attracted substantial attention owing to their potential application in various industries. Conventional textiles used in daily life are prone to staining with water and household liquids, necessitating the development of water-repellent and stain-resistant coatings. In this study, we fabricated a highly water-repellent superhydrophobic PET fabric by using an eco-friendly water-based coating process. Fluorine-free octadecyltrichlorosilane (OTS) solutions with various wt.% of hollow silica (HS) nanoparticles were used to produce a superhydrophobic surface via a facile dip coating method. Our findings revealed that the incorporation of HS nanoparticles substantially increased the water contact angle, with higher concentrations resulting in enhanced water repellency and increased surface roughness. The treated fabrics had a remarkable water contact angle of 152.4° ± 0.8°, demonstrating their superhydrophobic fiber surface. In addition, the durability of these superhydrophobic properties was investigated via a laundry procedure, which showed that the fabrics maintained their water repellency even after 20 laundering cycles. EDX and XRD analyses confirmed that the morphological evaluations did not reveal any substantial structural alterations. Significantly, the fibers maintained their strength and durability throughout the testing, enduring only minor hollow SiO₂ nanoparticle loss. This eco-friendly and cost-effective method holds great potential for application in apparel and other industries, offering an effective solution to resist water stains and improve performance in various contexts. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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10 pages, 2730 KiB

Open AccessCommunication

Control of Bandgaps and Energy Levels in Water-Soluble Discontinuously Conjugated Polymers through Chemical Modification

by Hao-Xuan Guo, Riho Higashida and Hiroyuki Aota

Polymers 2023, 15(12), 2738; https://doi.org/10.3390/polym15122738 - 19 Jun 2023

Cited by 1 | Viewed by 838

Abstract

Bandgap and energy levels are crucial for developing new electronic and photonic devices because photoabsorption is highly dependent on the bandgap. Moreover, the transfer of electrons and holes between different materials depends on their respective bandgaps and energy levels. In this study, we [...] Read more.

Bandgap and energy levels are crucial for developing new electronic and photonic devices because photoabsorption is highly dependent on the bandgap. Moreover, the transfer of electrons and holes between different materials depends on their respective bandgaps and energy levels. In this study, we demonstrate the preparation of a series of water-soluble discontinuously π-conjugated polymers through the addition–condensation polymerization of pyrrole (Pyr), 1,2,3-trihydroxybenzene (THB) or 2,6-dihydroxytoluene (DHT), and aldehydes, including benzaldehyde-2-sulfonic acid sodium salt (BS) and 2,4,6-trihydroxybenzaldehyde (THBA). To control the energy levels of the polymers, varying amounts of phenols (THB or DHT) were introduced to alter the electronic properties of the polymer structure. The introduction of THB or DHT into the main chain results in discontinuous conjugation and enables the control of both the energy level and bandgap. Chemical modification (acetoxylation of phenols) of the polymers was employed to further tune the energy levels. The optical and electrochemical properties of the polymers were also investigated. The bandgaps of the polymers were controlled in the range of 0.5–1.95 eV, and their energy levels could also be effectively tuned. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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11 pages, 2029 KiB

Open AccessArticle

Polymerization of Allyltrimethylisilane and 4-Methyl-1-Pentene by Using Metallocene Catalysts

by Wei Wang, Minqiao Ren, Liping Hou, Shuzhang Qu, Xinwei Li and Zifang Guo

Polymers 2023, 15(9), 2038; https://doi.org/10.3390/polym15092038 - 25 Apr 2023

Cited by 1 | Viewed by 1323

Abstract

Polymers of higher olefin, obtained by Ziegler-type polymerization, have been used in some critical fields, e.g., as the membrane for extracorporeal membrane oxygenation (ECMO), which plays an important role in the treatment of patients with severe COVID-19. The polymer obtained by a single-site [...] Read more.

Polymers of higher olefin, obtained by Ziegler-type polymerization, have been used in some critical fields, e.g., as the membrane for extracorporeal membrane oxygenation (ECMO), which plays an important role in the treatment of patients with severe COVID-19. The polymer obtained by a single-site catalyst, e.g., metallocene catalysts, demonstrated a higher performance. The homo- and co-polymerization of allyltrimethylisilane (ATMS) and 4-methyl-1-pentene (4M1P) were conducted using syndiospecific (cat 1) and isospecific (cat 2) metallocene catalysts. Cat 1 showed low conversions and provided a polymer with a higher molecular weight, while cat 2 behaved oppositely. ¹³C-NMR spectra certified the stereotacticity of the resultant polymer, and the resonance of the carbon atom of CH₂ (αα’) between the two tertiary carbon atoms of the ATMS and 4M1P units were observed. This could be the evidence of the formation of a true copolymer. The crystallization of the polymer was explored using a differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD). All homopolymers and some of the copolymers showed high melting temperatures and low melting enthalpies. The WAXD patterns of the syndiotactic polymer and isotactic homopolymer or the ATMS-rich copolymer were consistent with the reported literature, but the isotactic 4M1P-rich copolymer provided the crystal form I, which is unusual for a 4M1P polymer without any pretreatment. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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14 pages, 4832 KiB

Open AccessArticle

Ultra-High Molecular Weight Polyethylene Modifications Produced by Carbon Nanotubes and Fe₂O₃ Nanoparticles

by Alfio Torrisi, Lorenzo Torrisi, Mariapompea Cutroneo, Alena Michalcova, Milena D’Angelo and Letteria Silipigni

Polymers 2023, 15(5), 1169; https://doi.org/10.3390/polym15051169 - 25 Feb 2023

Cited by 1 | Viewed by 1830

Abstract

Thin sheets of ultra-high molecular weight polyethylene (UHMWPE), both in pristine form and containing carbon nanotubes (CNTs) or Fe₂O₃ nanoparticles (NPs) at different concentrations, were prepared. The CNT and Fe₂O₃ NP weight percentages used ranged from 0.01% [...] Read more.

Thin sheets of ultra-high molecular weight polyethylene (UHMWPE), both in pristine form and containing carbon nanotubes (CNTs) or Fe₂O₃ nanoparticles (NPs) at different concentrations, were prepared. The CNT and Fe₂O₃ NP weight percentages used ranged from 0.01% to 1%. The presence of CNTs and Fe₂O₃ NPs in UHMWPE was confirmed by transmission and scanning electron microscopy and by energy dispersive X-ray spectroscopy analysis (EDS). The effects of the embedded nanostructures on the UHMWPE samples were studied using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and UV–Vis absorption spectroscopy. The ATR-FTIR spectra show the characteristic features of the UHMWPE, CNTs, and Fe₂O₃. Concerning the optical properties, regardless of the type of embedded nanostructures, an increase in the optical absorption was observed. The allowed direct optical energy gap value was determined from the optical absorption spectra: in both cases, it decreases with increasing CNT or Fe₂O₃ NP concentrations. The obtained results will be presented and discussed. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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17 pages, 4738 KiB

Open AccessArticle

Graphene Oxide and Polymer Humidity Micro-Sensors Prepared by Carbon Beam Writing

by Petr Malinský, Oleksander Romanenko, Vladimír Havránek, Mariapompea Cutroneo, Josef Novák, Eva Štěpanovská, Romana Mikšová, Petr Marvan, Vlastimil Mazánek, Zdeněk Sofer and Anna Macková

Polymers 2023, 15(5), 1066; https://doi.org/10.3390/polym15051066 - 21 Feb 2023

Cited by 3 | Viewed by 1390

Abstract

In this study, novel flexible micro-scale humidity sensors were directly fabricated in graphene oxide (GO) and polyimide (PI) using ion beam writing without any further modifications, and then successfully tested in an atmospheric chamber. Two low fluences (3.75 × 10¹⁴ cm⁻² [...] Read more.

In this study, novel flexible micro-scale humidity sensors were directly fabricated in graphene oxide (GO) and polyimide (PI) using ion beam writing without any further modifications, and then successfully tested in an atmospheric chamber. Two low fluences (3.75 × 10¹⁴ cm⁻² and 5.625 × 10¹⁴ cm⁻²) of carbon ions with an energy of 5 MeV were used, and structural changes in the irradiated materials were expected. The shape and structure of prepared micro-sensors were studied using scanning electron microscopy (SEM). The structural and compositional changes in the irradiated area were characterized using micro-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Rutherford back-scattering spectroscopy (RBS), energy-dispersive X-ray spectroscopy (EDS), and elastic recoil detection analysis (ERDA) spectroscopy. The sensing performance was tested at a relative humidity (RH) ranging from 5% to 60%, where the electrical conductivity of PI varied by three orders of magnitude, and the electrical capacitance of GO varied in the order of pico-farads. In addition, the PI sensor has proven long-term sensing stability in air. We demonstrated a novel method of ion micro-beam writing to prepare flexible micro-sensors that function over a wide range of humidity and have good sensitivity and great potential for widespread applications. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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20 pages, 12153 KiB

Open AccessArticle

Characteristics of Composite Materials of the Type: TPU/PP/BaTiO₃ Powder for 3D Printing Applications

by Romeo Cristian Ciobanu, Cristina Schreiner, Mihaela Aradoaei, Gabriela Elen Hitruc, Bogdan-George Rusu and Magdalena Aflori

Polymers 2023, 15(1), 73; https://doi.org/10.3390/polym15010073 - 24 Dec 2022

Cited by 4 | Viewed by 2024

Abstract

Composite materials are materials with anisotropic properties that are created by combining several different components in a way that allows the best qualities of each component to be used. In this paper, raw materials were used to obtain composite materials of the type [...] Read more.

Composite materials are materials with anisotropic properties that are created by combining several different components in a way that allows the best qualities of each component to be used. In this paper, raw materials were used to obtain composite materials of the type TPU/PP/BaTiO₃ powder. The thermogravimetric analysis, dynamic differential calorimetry, and scanning electron microscopy were carried out. The preliminary tests for making specific filaments for 3D printing with a diameter of 1.75 mm were carried out on a laboratory extruder. The purpose of the experiment was to develop the optimal extrusion temperatures and the speed of drawing the filament to make filaments with rigorously constant dimensions, and the variation in diameter had a maximum of 10%. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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Review

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56 pages, 23029 KiB

Open AccessReview

Progress and Prospect of Ion Imprinting Technology in Targeted Extraction of Lithium

by Keke Zhi, Jinwang Duan, Jiarui Zhang, Lianting Huang, Lianghui Guo and Lulu Wang

Polymers 2024, 16(6), 833; https://doi.org/10.3390/polym16060833 - 18 Mar 2024

Viewed by 669

Abstract

Ion Imprinting Technology (IIT) is an innovative technique that produces Ion-Imprinted polymers (IIPs) capable of selectively extracting ions. IIPs exhibit strong specificity, excellent stability, and high practicality. Due to their superior characteristics, the application of IIPs for lithium resource extraction has garnered significant [...] Read more.

Ion Imprinting Technology (IIT) is an innovative technique that produces Ion-Imprinted polymers (IIPs) capable of selectively extracting ions. IIPs exhibit strong specificity, excellent stability, and high practicality. Due to their superior characteristics, the application of IIPs for lithium resource extraction has garnered significant attention. This paper discusses the following aspects based on existing conventional processes for lithium extraction and the latest research progress in lithium IIPs: (1) a detailed exposition of existing lithium extraction processes, including comparisons and summaries; (2) classification, comparison, and summarization of the latest lithium IIPs based on different material types and methods; (3) summarization of the applications of various lithium IIPs, along with a brief description of future directions in the development of lithium IIP applications. Finally, the prospects for targeted recovery of lithium resources using lithium IIPs are presented. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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23 pages, 4044 KiB

Open AccessReview

A Comprehensive Review on Processing, Development and Applications of Organofunctional Silanes and Silane-Based Hyperbranched Polymers

by Balaraman Indumathy, Ponnan Sathiyanathan, Gajula Prasad, Mohammad Shamim Reza, Arun Anand Prabu and Hongdoo Kim

Polymers 2023, 15(11), 2517; https://doi.org/10.3390/polym15112517 - 30 May 2023

Cited by 7 | Viewed by 3103

Abstract

Since the last decade, hyperbranched polymers (HBPs) have gained wider theoretical interest and practical applications in sensor technology due to their ease of synthesis, highly branched structure but dimensions within nanoscale, a larger number of modified terminal groups and lowering of viscosity in [...] Read more.

Since the last decade, hyperbranched polymers (HBPs) have gained wider theoretical interest and practical applications in sensor technology due to their ease of synthesis, highly branched structure but dimensions within nanoscale, a larger number of modified terminal groups and lowering of viscosity in polymer blends even at higher HBP concentrations. Many researchers have reported the synthesis of HBPs using different organic-based core-shell moieties. Interestingly, silanes, as organic-inorganic hybrid modifiers of HBP, are of great interest as they resulted in a tremendous improvement in HBP properties like increasing thermal, mechanical and electrical properties compared to that of organic-only moieties. This review focuses on the research progress in organofunctional silanes, silane-based HBPs and their applications since the last decade. The effect of silane type, its bi-functional nature, its influence on the final HBP structure and the resultant properties are covered in detail. Methods to enhance the HBP properties and challenges that need to be overcome in the near future are also discussed. Full article

(This article belongs to the Special Issue Innovative and Functionalized Polymers: Processing, Development and Applications)

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