Outstanding high-temperature resistance, thermal stability, and dielectric properties are fundamental for dielectric materials used in harsh environments. Herein, TiOsub.2 nanoparticles are decorated ...on the surface of BN nanosheets by internal crosslinking between polydopamine (PDA) and polyethyleneimine (PEI), forming three-dimensional novel nanohybrids with a rough surface. Then, an ether nitrile (PEN) matrix is introduced into the polyarylene to form polymer-based nanocomposite dielectric films. Meanwhile, the structure and micromorphology of the newly prepared nanohybrids, as well as the dielectric and thermal properties of PEN nanocomposites, are investigated in detail. The results indicate that TiOsub.2 nanoparticles tightly attach to the surface of BN, creating a new nanohybrid that significantly enhances the comprehensive performance of PEN nanocomposites. Specifically, compared to pure PEN, the nanocomposite film with a nanofiller content of 40 wt% exhibited an 8 °C improvement in the glass transition temperature (Tsub.g) and a 162% enhancement in the dielectric constant at 1 kHz. Moreover, the dielectric constant–temperature coefficient of the nanocomposite films remained below 5.1 × 10sup.−4 °Csup.−1 within the temperature range of 25–160 °C, demonstrating excellent thermal resistance. This work offers a method for preparing highly thermal-resistant dielectric nanocomposites suitable for application in elevated temperature environments.
PEDOT:PSS is a commonly used hole-transport layer (HTL) in inverted perovskite solar cells (PSCs) due to its compatibility with low-temperature solution processing. However, it possesses lower ...conductivity than other conductive polymers and metal oxides, along with surface defects, limiting its photovoltaic performance. In this study, we introduced two-dimensional Tisub.3Csub.2Tsub.x (MXene) as an additive in the PEDOT:PSS HTL with varying doping concentrations (i.e., 0, 0.03, 0.05, and 0.1 wt.%) to tune the electrical conductivity of PEDOT:PSS and to modify the properties of the perovskite film atop it. We noted that the grain size of the CHsub.3NHsub.3PbIsub.3 (MAPIsub.3) perovskite layer grown over an optimal concentration of MXene (0.03 wt.%)-doped PEDOT:PSS increased from 250 nm to 400 nm, reducing charge recombination due to fewer grain boundaries. Ultraviolet photoelectron spectroscopy (UPS) revealed increased work function (WF) from 4.43 eV to 4.99 eV with 0.03 wt.% MXene doping, making the extraction of holes easier due to a more favorable energy level alignment with the perovskite. Quantum chemical investigations based on density functional theory (DFT) were conducted at the ωB97XD/6-311++G(d,p) level of theory to provide more insight into the stability, bonding nature, and optoelectronic properties of the PEDOT:PSS-MXene system. The theoretical investigations revealed that the doping of PEDOT:PSS with Tisub.3Csub.2Tsub.x could cause a significant effect on the electronic properties of the HTL, as experimentally demonstrated by an increase in the electrical conductivity. Finally, the inverted PSCs employing 0.03 wt.% MXene-doped PEDOT:PSS showed an average power conversion efficiency (PCE) of 15.1%, up from 12.5% for a reference PSC employing a pristine PEDOT:PSS HTL. The champion device with a 0.03 wt.% MXene-PEDOT:PSS HTL achieved 15.5% PCE.
The accumulation and fragmentation of plastics in water sources is one of the important problems of recent times. In this study, it was aimed to determine and characterize the microplastic ...accumulation in the sediment and in the stomach and gills of the freshwater crayfish Astacus leptodactylus (Eschscholtz 1823) in Durusu (Terkos) Lake, which is one of the most important water resources of Istanbul and even the Marmara Region. Thus, the microplastic contamination of both the lake sediment and crayfish was revealed for the first time in Turkey, and insight was given into the transmission of this contamination to the biota. The microplastic amount of the sediment samples was found as 32.26-396.71 pieces.kg.sup.-1 dry sediment. The microplastic amount was determined as 0.89-15.67 pieces.ind.sup.-1 in stomach content and 0.5-19.67 pieces.ind.sup.-1 in the gills of the crayfish. The predominant microplastic types were found as fragments in the sediment samples, fibers in the gill, and stomach content. As a result of the analysis, the main polymers identified in crayfish samples were polypropylene (78%) and followed by polyphenylene sulfide (11%) and polyethylene (11%); in sediment samples, polypropylene (47%) and followed by polyvinyl alcohol (20%), polyethylene (20%), and polyamide (13%). Activities carried out in the coastal area pollute the lake, and it is necessary to control the anthropogenic and fisheries-related pollution in the lake.
In this study, experimental investigations were performed to gain insights into the processing parameter effects of laser-assisted automated fibre placement (AFP) on the mechanical properties of ...carbon fibre (CF)/polyphenylene sulphide (PPS) composites from the perspective of void content and crystallinity. First, thermal characterisation was carried out to obtain the processing window for the PPS/CF composites. The temperature histories at the nip point during an AFP process were measured using an in-house temperature measurement system and the desired ranges of laser power and placement rate were determined based on the measured temperatures. The placement rate was ranging from 6 to 60 m/min, and the range of the used laser power was 1–6 kW. Then, the effects of tool temperature ranging from 30 to 120 °C on the interlaminar shear strength and compression strength of the CF/PPS composites were examined. It was found that the interlaminar void content dominated the mechanical properties of the composite rather than the crystallinity. Finally, the composites produced by the AFP were further treated by an autoclave. It was shown that the interlaminar shear strength of the composites was significantly improved after the autoclave post-consolidation treatment due to the reduction in void content and the improvement of crystallinity. The interlaminar shear strength of the composites after the autoclave treatment was found to be independent of the placement rate, indicating elimination of the AFP thermal history due to sufficient heating and compaction time in the autoclave.
In this study, a composite material consisting of perfluorinated quaternary silane-modified graphene oxide and modified CeO2 nanoparticles was prepared, and a hydrophobic, corrosion-resistant, ...self-cleaning and anti-icing composite coating was prepared by combining the composite material with polyphenylene sulfide (PPS) through high-temperature curing in a simple spraying method for the protection of iron sheets. The results show that the composite coating has excellent corrosion resistance, strong mechanical properties and certain photothermal properties. When the content of perfluorinated quaternary silane modified modified CeO2 nanoparticles with graphene oxide (P-GKC) was 10wt%, the composite coating had a water contact angle of 145.6 ± 3° and a sliding angle of 5 ± 1°, with good hydrophobicity and low surface energy. Meanwhile, the hydrophobic modification of perfluoroquaternary silanes reduced the surface energy of the particles in the composite coatings and greatly improved the hydrophobicity. Surface temperature and laser irradiation tests of the composite coatings showed that the photothermal properties of the composite coatings were better than those of the single PPS and graphene oxide (GO) coatings, with good photothermal cycling stability.The Tafel curves and the EIS results showed that the PPS/10wt% P-GKC composite coatings had the best corrosion resistance, with a corrosion current density of 5.01 × 10-9A·cm-2. After 200h of salt spray test in 3.5% NaCl environment, the PPS/10wt% P-GKC composite coating still has good substrate protection effect, which provides a practical basis for the research of composite coating anticorrosion.
Display omitted
This study presents a direct electrochemical modification technique for incorporating two specific small molecules, phenol, and aniline into carbon fibre (CF) surface. These molecules have a strong ...hydrogen bonding for polyphenylene sulphide (PPS) and are intended to improve the friction and wear properties of PPS/CF composites. The tribological properties of PPS/CF composites were evaluated using a pin-on-disc. To get a more thorough comprehension of the working conditions of PPS/CF composites, a comparative examination of the composites' tribological characteristics was carried out by modifying the nature of the opposing surface while keeping the sliding speed of the applied force consistent. The results showed that the addition of 10 mM phenol to carbon fibre results in a significant reduction in the coefficient of friction (COF) compared to carbon fibre treated with 50 mM phenol and 6 mM aniline when in contact with a steel counter-face. When sliding against a polymer counter-face, the composites experienced a reduction in the COF due to the formation of a transfer film rich in PPS. Introducing aniline groups to the fibre surface reduced the wear rate by 57.5% to 46% with applied forces of 25 N compared to PPS and unmodified PPS/CF when sliding against the polymer counter-face. This study thoroughly discusses the synergistic process of chemical modification on the tribological performance of PPS/CF. It also analyses the surface microstructures of the worn surfaces of the composites. This study has the potential to provide new insights into the design and development of CF/polymer composites with enhanced friction and wear properties.
Display omitted
•Chemical modification of carbon fibre surface-reinforcing thermoplastics on tribological performance was studied.•The relationship between the counter-face effect and tribological performance was analysed.•The wear rate and coefficient of friction of different PPS/CF composites were compared.•The optimum carbon fibre surface modification was proposed to enhance the tribological performance.
The high coefficient of thermal expansion (CTE) of polymeric composites can cause large deformation under temperature changes, affecting coupling with devices made of other materials in radio ...frequency (RF) communication systems and limiting their application in RF systems. In order to obtain polyphenylene sulphide (PPS)-based composites with low CTE, a series of PPS-based composites containing different loadings of ceramic powders (including Zr2WP2O12, BN, AlN, Al2O3) were fabricated by melt extrusion method using PPS with 40 wt% glass fibre (GF) as matrix material. The experimental results showed that the PPS composites with Zr2WP2O12 (ZWP) as a filler had a lower CTE compared to the samples with other fillers at the same filler loading. The CTE of PPS/GF/ZWP steadily decreased with increasing ZWP addition. At 20 vol% ZWP loading, a 67% (about 18 ppm/°C) reduction of CTE compared to the PPS/GF was achieved. The addition of ZWP powder to PPS/GF also led to an improvement in the dielectric loss of the composite. When the ZWP content is 20 vol%, the dielectric loss of the composites is about 0.0035, which is 24.4% lower than PPS/GF. Hence, the PPS/GF/ZWP composites have great potential for applications in RF communication systems.
In this paper, two surface treatment technologies, i. e. sand blasting and plasma electrolytic oxidation (PEO), are respectively applied on magnesium alloy to increase joint strength of glass fibre ...reinforced polyphenylene sulphide (PPS)-Mg composite. The influence of treated metal's surface structure on the joint strength between PPS and Mg was carefully investigated. Three rupture mechanisms have been proposed, i.e. direct PPS peeling off, PPS rupturing at the interface as well as metal outmost layer detaching by the adhesion of PPS. Compared with the sand blasting technique, PEO treatment can achieve a much higher joint strength due to the formation of porous and uniform surface structure on the Mg alloys. This kind of structure is favourable for the joint strength between Mg and PPS due to the strong mechanical riveting. PEO technique is a promising technology to improve the joint strength between plastic and metal.
•PEO coated interface highly enhanced the joint strength of PPS-Mg composites.•Porous structures on the PEO coated Mg determine the joint strength of PPS-Mg.•Three rupture mechanisms of PPS-Mg composite were revealed.
This study investigates the thermal behaviour of discontinuous carbon fibre reinforced polyphenylene sulphide (CF/PPS), additively manufactured by material extrusion, with a focus on the effects of ...thermal process conditions on the degree of crystallinity, oxidation crosslinking and mechanical properties of CF/PPS from filament fabrication, material extrusion to annealing treatment. The screw extrusion parameters are optimised by performing a thermal analysis of the fabricated filaments. The effect of crosslinking reactions on the crystallinity process in determining the mechanical properties of the printed samples is illustrated by investigating the influence of the printing conditions. Furthermore, the effect of annealing treatment on the semi-crystalline polyphenylene sulphide (PPS) is studied by measuring the degree of crystallinity and viscoelasticity behaviours. Results demonstrate that the flexural properties of the printed CF/PPS composites at elevated processing temperatures are determined by the oxidation crosslinking between PPS chains. These enhance the crystallisation process of semi-crystalline polymers by acting as the nucleating agent first but negatively affect the mechanical properties at higher temperatures because of the detrimental effects of the polymer inter-chain bonding. The maximum flexural strength of printed CF/PPS reached 164.65 MPa when processing at an extrusion temperature of 280°C, a printing temperature of 320°C, and an annealing temperature of 130°C for 6 h. By adjusting the thermal treatment conditions, the degree of the crystallinity and the mechanical properties of the printed CF/PPS composites can be designed, controlled and tailored.
![Ti[sub.3]C[sub.2]T[sub.x]-M...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1420-3049/small "Ti[sub.3]C[sub.2]T[sub.x]-Modified PEDOT:PSS Hole-Transport Layer for Inverted Perovskite Solar Cells")
