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13 pages, 3455 KiB

Open AccessArticle

Induced Electron Traps via the PCBM in P(VDF-HFP) Composites to Enhance Dielectric and Energy Storage Performance

by Yantao Yang, Jingqi Qiao, Haiyu Sun, Wenhao Yang, Liangliang Wei and Xuetong Zhao

Polymers 2024, 16(21), 3030; https://doi.org/10.3390/polym16213030 - 29 Oct 2024

Viewed by 529

Abstract

Polymer-based composites with excellent dielectric properties are essential for advanced energy storage applications. In this work, the [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) as a filler was incorporated into the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) composite to improve its dielectric performance. P(VDF-HFP) composite films [...] Read more.

Polymer-based composites with excellent dielectric properties are essential for advanced energy storage applications. In this work, the [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) as a filler was incorporated into the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) composite to improve its dielectric performance. P(VDF-HFP) composite films with varying PCBM concentrations were prepared via solution casting and their dielectric, energy storage, and charge–discharge properties were characterized. It was found that the doped PCBM could introduce new charge traps with an energy level of 1.25 eV that modulate charge transport and energy storage characteristics of the polymer matrix. The dielectric constant of the composites was enhanced to the maximum of 10.87 as 0.2 vol% PCBM was added, while the breakdown strength reached 455 MV/m, achieving an energy density of 7.38 J/cm3, which is 33% higher than the pristine P(VDF-HFP) film. Furthermore, the charge–discharge efficiency of the composites was enhanced 66% under the electric field of 300 MV/m. These results demonstrate that PCBM significantly improves the dielectric and energy storage properties of P(VDF-HFP) composites, providing a promising approach for the development of high-performance dielectric materials in flexible energy storage devices. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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16 pages, 4790 KiB

Open AccessArticle

Synthesis of Ultrahigh Molecular Weight Poly (Trifluoroethyl Methacrylate) Initiated by the Combination of Palladium Nanoparticles with Organic Halides

by Jian Guan, Xiaodi Yu, Minghui He, Wenfeng Han, Ying Li, Zongjian Liu, Panpan Zhang and Haodong Tang

Polymers 2024, 16(19), 2764; https://doi.org/10.3390/polym16192764 - 30 Sep 2024

Viewed by 578

Abstract

Ultrahigh molecular weight polymers display outstanding properties and have great application potential. However, the traditional polymerization methods have inevitable disadvantages that challenge the green synthesis of ultrahigh molecular weight polymers. The paper achieved an ultrahigh molecular weight poly (trifluoroethyl methacrylate) via a novel [...] Read more.

Ultrahigh molecular weight polymers display outstanding properties and have great application potential. However, the traditional polymerization methods have inevitable disadvantages that challenge the green synthesis of ultrahigh molecular weight polymers. The paper achieved an ultrahigh molecular weight poly (trifluoroethyl methacrylate) via a novel polymerization and discussed the mechanistic, kinetic, and experimental aspects. The combination of palladium nanoparticles with ethyl 2-bromopropionate has been identified as an exceedingly efficient system for initiating the polymerization of trifluoroethyl methacrylate. An ultrahigh molecular weight poly (trifluoroethyl methacrylate) with a number-average molecular weight up to 3.03 × 10⁶ Da has been synthesized at a feeding molar ratio of [poly (trifluoroethyl methacrylate)]/[ethyl 2-bromopropionate]/[palladium nanoparticles] = 3.95 × 10⁴:756:1 at 70 °C. The reaction orders concerning palladium nanoparticles, ethyl 2-bromopropionate, and poly (trifluoroethyl methacrylate) were determined to be 0.59, 0.34, and 1.38, respectively. By analyzing a series of characterizations, we verified that the polymerization of poly (trifluoroethyl methacrylate) was initiated by the ethyl 2-bromopropionate residue radicals, which were generated from the interaction between palladium nanoparticles and ethyl 2-bromopropionate. The comparatively large size of the palladium nanoparticles provided a barrier to chain-growing radicals, promoting the synthesis of ultrahigh molecular weight polymers. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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23 pages, 6087 KiB

Open AccessArticle

Evaluation of Physicochemical Properties of a Hydroxyapatite Polymer Nanocomposite for Use in Fused Filament Fabrication

by Ngoc Mai Nguyen, Akesh Babu Kakarla, Satya Guha Nukala, Cin Kong, Avinash Baji and Ing Kong

Polymers 2023, 15(19), 3980; https://doi.org/10.3390/polym15193980 - 3 Oct 2023

Cited by 8 | Viewed by 2233

Abstract

Over the last decade, there has been an increasing interest in the use of bioceramics for biomedical purposes. Bioceramics, specifically those made of calcium phosphate, are commonly used in dental and orthopaedic applications. In this context, hydroxyapatite (HA) is considered a viable option [...] Read more.

Over the last decade, there has been an increasing interest in the use of bioceramics for biomedical purposes. Bioceramics, specifically those made of calcium phosphate, are commonly used in dental and orthopaedic applications. In this context, hydroxyapatite (HA) is considered a viable option for hard tissue engineering applications given its compositional similarity to bioapatite. However, owing to their poor mechanobiology and biodegradability, traditional HA-based composites have limited utilisation possibilities in bone, cartilage and dental applications. Therefore, the efficiency of nano HA (nHA) has been explored to address these limitations. nHA has shown excellent remineralising effects on initial enamel lesions and is widely used as an additive for improving existing dental materials. Furthermore, three-dimensional printing (3DP) or fused deposition modelling that can be used for creating dental and hard tissue scaffolds tailored to each patient’s specific anatomy has attracted considerable interest. However, the materials used for producing hard tissue with 3DP are still limited. Therefore, the current study aimed to develop a hybrid polymer nanocomposite composed of nHA, nanoclay (NC) and polylactic acid (PLA) that was suitable for 3DP. The nHA polymer nanocomposites were extruded into filaments and their physiochemical properties were evaluated. The results showed that the addition of nHA and NC to the PLA matrix significantly increased the water absorption and contact angle. In addition, the hardness increased from 1.04 to 1.25 times with the incorporation of nHA. In sum, the nHA-NC-reinforced PLA could be used as 3DP filaments to generate bone and dental scaffolds, and further studies are needed on the biocompatibility of this material. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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13 pages, 2329 KiB

Open AccessArticle

Effect of Cerium (IV) Oxide Particle Size on Polydimethylsiloxane Polymer to Form Flexible Materials against Ionizing Radiation

by Haifa M. Almutairi, Wafa M. Al-Saleh, Mohammad Ibrahim Abualsayed and Mohamed Elsafi

Polymers 2023, 15(13), 2883; https://doi.org/10.3390/polym15132883 - 29 Jun 2023

Cited by 9 | Viewed by 1347

Abstract

This study aims to investigate the impact of CeO₂ content and particle size on the radiation shielding abilities of polydimethylsiloxane, also known as silicon rubber (SR). We prepared different SR samples with 10, 30, and 50% of micro and nano CeO₂ [...] Read more.

This study aims to investigate the impact of CeO₂ content and particle size on the radiation shielding abilities of polydimethylsiloxane, also known as silicon rubber (SR). We prepared different SR samples with 10, 30, and 50% of micro and nano CeO₂ and we measured the linear attenuation coefficient (LAC) for these samples. We found that the LAC of the SR increases by increasing the CeO₂ and all prepared SR samples had higher LACs than the pure SR. We examined the effect of the size of the particles on the LAC and the results demonstrated that the LAC for nano CeO₂ is higher than that of micro CeO₂. We investigated the half value layer (HVL) for the prepared SR samples and the results revealed that the SR with 10% micro CeO₂ had a greater HVL than the SR with 10% nano CeO₂. The HVL results demonstrated that the SR containing nanoparticles had higher attenuation effectiveness than the SR with micro CeO₂. We also prepared SR samples containing CeO₂ in both sizes (i.e., micro and nano) and we found that the HVL of the SR containing both sizes was lower than the HVL of the SR with nano CeO₂. The radiation protection efficiency (RPE) at 0.059 MeV for the SR with 10% micro and nano CeO₂ was 94.2 and 95.6%, respectively, while the RPE of SR containing both sizes (5% micro CeO₂ + 5% micro CeO₂) was 96.1% at the same energy. The RPE results also indicated that the attenuation ability was improved when utilizing the micro and nano CeO₂ as opposed to the micro CeO₂ or nano CeO₂ at 0.662, 1.173, and 1.333 MeV. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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19 pages, 8657 KiB

Open AccessArticle

Characterization and Morphology of Nanocomposite Hydrogels with a 3D Network Structure Prepared Using Attapulgite-Enhanced Polyvinyl Alcohol

by Chi-Hui Tsou, Yu-Jie Shui, Juan Du, Wei-Hua Yao, Chin-San Wu, Maw-Cherng Suen and Shuang Chen

Polymers 2023, 15(11), 2535; https://doi.org/10.3390/polym15112535 - 31 May 2023

Cited by 3 | Viewed by 1479

Abstract

In this investigation, purified attapulgite (ATT) and polyvinyl alcohol (PVA) were utilized to fabricate nanocomposite hydrogels and a xerogel, with a focus on studying the impact of minor additions of ATT on the properties of the PVA nanocomposite hydrogels and xerogel. The findings [...] Read more.

In this investigation, purified attapulgite (ATT) and polyvinyl alcohol (PVA) were utilized to fabricate nanocomposite hydrogels and a xerogel, with a focus on studying the impact of minor additions of ATT on the properties of the PVA nanocomposite hydrogels and xerogel. The findings demonstrated that at a concentration of 0.75% ATT, the water content and gel fraction of the PVA nanocomposite hydrogel reached their peak. Conversely, the nanocomposite xerogel with 0.75% ATT reduced its swelling and porosity to the minimum. SEM and EDS analyses revealed that when the ATT concentration was at or below 0.5%, nano-sized ATT could be evenly distributed in the PVA nanocomposite xerogel. However, when the concentration of ATT rose to 0.75% or higher, the ATT began to aggregate, resulting in a decrease in porous structure and the disruption of certain 3D porous continuous structures. The XRD analysis further affirmed that at an ATT concentration of 0.75% or higher, a distinct ATT peak emerged in the PVA nanocomposite xerogel. It was observed that as the content of ATT increased, the concavity and convexity of the xerogel surface, as well as the surface roughness, decreased. The results also confirmed that the ATT was evenly distributed in the PVA, and a combination of hydrogen bonds and ether bonds resulted in a more stable gel structure. The tensile properties exhibited that when compared with pure PVA hydrogel, the maximum tensile strength and elongation at break were achieved at an ATT concentration of 0.5%, indicating increases of 23.0% and 11.8%, respectively. The FTIR analysis results showed that the ATT and PVA could generate an ether bond, further confirming that ATT could enhance the PVA properties. The TGA analysis showed that the thermal degradation temperature peaked when the ATT concentration was at 0.5%, providing further evidence that the compactness of the nanocomposite hydrogel and the dispersion of the nanofiller was superior, contributing to a substantial increase in the mechanical properties of the nanocomposite hydrogel. Finally, the dye adsorption results displayed a significant rise in dye removal efficiency for methylene blue with the increase in the ATT concentration. At an ATT concentration of 1%, the removal efficiency rose by 103% compared with that of the pure PVA xerogel. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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25 pages, 27991 KiB

Open AccessArticle

Flexible Electromagnetic Shielding Nano-Composites Based on Silicon and NiFe₂O₄ Powders

by Alina R. Caramitu, Romeo C. Ciobanu, Ioana Ion, Cristina M. Schreiner, Mihaela Aradoaei, Violeta Tsakiris, Jana Pintea and Virgil Marinescu

Polymers 2023, 15(11), 2447; https://doi.org/10.3390/polym15112447 - 25 May 2023

Cited by 5 | Viewed by 1961

Abstract

In this paper, the obtaining and characterization of five experimental models of novel polymer composite materials with ferrite nano-powder are presented. The composites were obtained by mechanically mixing two components and pressing the obtained mixture on a hot plate press. The ferrite powders [...] Read more.

In this paper, the obtaining and characterization of five experimental models of novel polymer composite materials with ferrite nano-powder are presented. The composites were obtained by mechanically mixing two components and pressing the obtained mixture on a hot plate press. The ferrite powders were obtained by an innovative economic co-precipitation route. The characterization of these composites consisted of physical and thermal properties: hydrostatic density, scanning electron microscopy (SEM), and TG DSC thermal analyses, along with functional electromagnetic tests in order to demonstrate the functionality of these materials as electromagnetic shields (magnetic permeability, dielectric characteristics, and shielding effectiveness). The purpose of this work was to obtain a flexible composite material, applicable to any type of architecture for the electrical and automotive industry, necessary for protection against electromagnetic interference. The results demonstrated the efficiency of such materials at lower frequencies, but also in the microwave domain, with higher thermal stability and lifetime. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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19 pages, 5874 KiB

Open AccessArticle

Polyaniline-Supported Nickel Oxide Flower for Efficient Nitrite Electrochemical Detection in Water

by Nada S. Al-Kadhi, Mahmoud A. Hefnawy, Fowzia S. Alamro, Rami Adel Pashameah, Hoda A. Ahmed and Shymaa S. Medany

Polymers 2023, 15(7), 1804; https://doi.org/10.3390/polym15071804 - 6 Apr 2023

Cited by 25 | Viewed by 2673

Abstract

A modified electrode with conducting polymer (Polyaniline) and NiO nanoflowers was prepared to detect nitrite ions in drinking water. A simple method was used to prepare the NiO nanoflower (NiOnF). Several techniques characterized the as-prepared NiOnF to determine the chemical structure and surface [...] Read more.

A modified electrode with conducting polymer (Polyaniline) and NiO nanoflowers was prepared to detect nitrite ions in drinking water. A simple method was used to prepare the NiO nanoflower (NiOnF). Several techniques characterized the as-prepared NiOnF to determine the chemical structure and surface morphology of the NiO, such as XRD, XPS, FT-IR, and TGA. The activity of the electrode toward nitrite sensing was investigated over a wide range of pH (i.e., 2 to 10). The amperometry method was used to determine the linear detection range and limit. Accordingly, the modified electrode GC/PANI/NiOnf showed a linear range of detection at 0.1–1 µM and 1–500 µM. At the same time, the limit of detection (LOD) was 9.7 and 64 nM for low and high concentrations, respectively. Furthermore, the kinetic characteristics of nitrite, such as diffusion and transport coefficients, were investigated in various media. Moreover, the charge transfer resistance was utilized for nitrite electrooxidation in different pH values by the electrochemical impedance technique (EIS). The anti-interfering criteria of the modified surfaces were utilized in the existence of many interfering cations in water (e.g., K⁺, Na⁺, Cu²⁺, Zn²⁺, Ba²⁺, Ca²⁺, Cr²⁺, Cd²⁺, Pd²⁺). A real sample of the Nile River was spiked with nitrite to study the activity of the electrode in a real case sample (response time ~4 s). The interaction between nitrite ions and NiO{100} surface was studied using DFT calculations as a function of adsorption energy. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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Review

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36 pages, 11033 KiB

Open AccessReview

State-of-the-Art Polyurea Coatings: Synthesis Aspects, Structure–Properties Relationship, and Nanocomposites for Ballistic Protection Applications

by Gabriela Toader, Aurel Diacon, Sorin Mircea Axinte, Alexandra Mocanu and Edina Rusen

Polymers 2024, 16(4), 454; https://doi.org/10.3390/polym16040454 - 6 Feb 2024

Cited by 4 | Viewed by 4106

Abstract

This review presents polyurea (PU) synthesis, the structure–properties relationship, and characterization aspects for ballistic protection applications. The synthesis of polyurea entails step-growth polymerization through the reaction of an isocyanate monomer/prepolymer and a polyamine, each component possessing a functionality of at least two. A [...] Read more.

This review presents polyurea (PU) synthesis, the structure–properties relationship, and characterization aspects for ballistic protection applications. The synthesis of polyurea entails step-growth polymerization through the reaction of an isocyanate monomer/prepolymer and a polyamine, each component possessing a functionality of at least two. A wide range of excellent properties such as durability and high resistance against atmospheric, chemical, and biological factors has made this polymer an outstanding option for ballistic applications. Polyureas are an extraordinary case because they contain both rigid segments, which are due to the diisocyanates used and the hydrogen points formed, and a flexible zone, which is due to the chemical structure of the polyamines. These characteristics motivate their application in ballistic protection systems. Polyurea-based coatings have also demonstrated their abilities as candidates for impulsive loading applications, affording a better response of the nanocomposite-coated metal sheet at the action of a shock wave or at the impact of a projectile, by suffering lower deformations than neat metallic plates. Full article

(This article belongs to the Special Issue Nanopolymers and Nanocomposites)

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