Polyphenylene Sulfide Research Articles

Prediction and Optimization of Interlayer-Interface Resistance for Expanded Polytetrafluoroethylene-Laminated Polyphenylene Sulfide Composite Membranes

Prediction and Optimization of Interlayer-Interface Resistance for Expanded Polytetrafluoroethylene-Laminated Polyphenylene Sulfide Composite Membranes

Anisotropic thermal behavior of extrusion‐based large scale additively manufactured carbon‐fiber reinforced thermoplastic structures

AbstractLarge format additive manufacturing (AM) enables rapid manufacturing of large parts and structures with minimum waste in material and energy. Extrusion‐based AM deposition processes provide parts with highly anisotropic thermal properties, which are not typically reflected in textbook values for these materials. In order to develop accurate models that describe the directionally dependent thermal behavior of these materials in processing and service, accurate measurements of specific heat capacity and thermal conductivity are required. This work characterizes, documents, and analyzes the effect of the anisotropic nature of the extrusion‐based deposition process on the specific heat capacity and thermal conductivity of the resulting AM products. All measurements were made over a temperature range of 20–180°C using the transient plane source technique, also referred to as the hot disk technique. Three of the most commonly used large format AM feedstock materials that utilize carbon fiber reinforcement were examined in this work: acrylonitrile butadiene styrene, polyphenylene sulfide and polyphenylsulfone. These findings can serve as a thermal design/process guideline for future large format AM applications.

A superhydrophobic polyphenylene sulfide composite coating with anti-corrosion and self-cleaning properties for metal protection

The poor corrosion resistance of metals has greatly limited its application. In this work, a simple spraying method was used for preparing SiO2/HDTMS-ZnO/PPS superhydrophobic composite coating. The water contact angle of the obtained coating is (150 ± 1) °, and the sliding angle is (3 ± 1) °. Due to its good hydrophobicity, it can resist muddy water. The test results of thermogravimetric (TG) indicate the outstanding thermal stability of the prepared coating with a quality loss of less than 10% under 493 °C. In addition, electrochemical testing shows that the composite coating exhibits excellent corrosion resistance, and the corrosion efficiency reaches 99.881%. Therefore, this superhydrophobic composite coating with antifouling, heat stability, and corrosion resistance has significant advantages in metal protection and is expected to be used for real application in corrosion protection.

Application of machine learning approaches to predict joint strength of friction stir welded aluminium alloy 7475 and PPS polymer hybrid joint

Vehicle weight has been a critical concern in the aerospace and automobile industries for decades. Integrating dissimilar aluminium and polymer hybrid structures is beneficial for weight reduction without affecting structural performance. In the present work, aluminium alloy 7475 and polyphenylene sulfide (PPS) sheets were joined using the friction stir welding (FSW) technology in lap joint configuration. A series of FSW experiments have been performed by the design matrix developed using response surface methodology. Tensile lap shear strength (TLS) is calculated for each experimental run. In this study, an attempt has been made to assess the potential of machine learning algorithms to predict the TLS of the joint. It was found that the support vector machine (SVM) model with RBF kernel was the most effective for predicting the TLS. Furthermore, FSW process parameters are optimized by means of the desirability approach. The optimal set to attain maximum TLS is identified as the tilt angle of 2°, welding speed of 5.12 mm/min and tool rotational speed of 1185.92 r/min. Finally, a confirmation test was performed to validate the optimal set and the adequacy of the developed SVM model. From the confirmation test, the error percentage between experimental and prediction values is less than 5%. Metallographic analysis revealed that the joining mechanism is the macro and micromechanical interlocking assisted by chemical bonding.

Combined effect of interfacial modification and α-ZrP reinforcement on the tribological properties of PPS fabric/phenolic composites

The high strength of polyphenylene sulfide (PPS) fiber subserves the potential application of PPS fabric composites in the field of tribology, but its interfacial adhesion restricts tribological properties. In this research, the 3-(2, 3-epoxy propoxy) propyl trimethoxy silane (KH560) was used to construct a micro-interface on the surface of the fabric, which can significantly enhance the surface roughness and functional groups. Furthermore, the incorporation of Alpha-zirconium phosphate (α-ZrP), a two-dimensional material with excellent thermal stability and chemical resistance, contributed to ameliorate thermal properties of the fabric composites. The results show that the bonding and tensile strength of the modified fabric composites are increased by 32.6% and 35.8%, respectively. More importantly, the wear rate of the modified fabric composites is reduced by 58.5% compared with the original fabric composites.

Shear Strength of Adhesive Bonding of Plastics Intended for High Temperature Plastic Radiators

The use of adhesive joints has increased in recent decades due to their competitive features in comparison with other joining methods. They can be used in specific applications where there is no possibility to use alternative connection techniques. Adhesive bonding was used to assemble the prototype of a high-temperature car radiator (operated up to 125 °C) with a total of 12,240 plastic tubes. This work aims to estimate the shear strength of different adhesives intended for bonding the plastics used to assemble the above-mentioned high-temperature radiator. Fourteen commercial adhesives were tested with one thermoset plastic (G11 glass fabric epoxy sheets) and two glass-reinforced thermoplastics (polyamide PA66-GF30 and polyphenylene sulfide PPS-GF40). Tests were conducted according EN 1465 to determine tensile lap-shear strength of bonding. Testing showed that only 4 of the 14 adhesives tested exhibit substantial bonding strength at temperatures above 120 °C and only one is resistant at 180 °C. The AS60/AW60 adhesive showed the best results for all three substrates: 1.6 MPa for epoxy sheets and PA66-GF, and 1.4 MPa for PPS-GF40. Additionally, the influence of the surface treatment with cold plasma was evaluated on a clean and activated bonding surface, causing a 30% increase in the shear strength.

Formation, stability and degradation of transfer films formed by polyphenylene sulfide (PPS) and its composites in dry sliding against steel

Transfer films are known to be important determinants of friction and wear, specifically in dry sliding of polymers on metals. Still, the kinetics of transfer film formation, the stability of transfer films, the in-situ correlation of friction and the extent of transfer film formation, are not yet fully understood. The main reason for this is the lack of time-resolved quantitative data on transfer film formation. Therefore, Transfer Film Luminance Analysis (TLA) was applied to block-on-ring sliding wear tests of polyphenylene sulfide (PPS) and selected PPS composites containing graphite, polytetrafluoroethylene (PTFE) and short carbon fibers (SCF) against steel. Though fundamental in nature, the tests’ parameters were chosen to closely match the operating conditions of dry-running bushings. While PPS filled with graphite or PTFE formed laterally homogeneous and temporally stable transfer films, SCF-containing composites exhibited recurrent spontaneous partial degradation of the transfer film. Significant fluctuations of the coefficient of friction (COF) were found to be the result these. Notably, when the extent of transfer film formation is reduced by such degradations, friction increased. Regarding material composition, mixed fiber/solid lubricant grades still exhibited transfer film instabilities and COF fluctuations, albeit at a much lower level. At the same time, no impact of partial transfer film degradation on wear was found.

Recent developments in tensile properties of friction welding of carbon fiber-reinforced composite: A review

Abstract In this review article, the joining of carbon fiber-reinforced polymer composite with metallic materials by using friction welding techniques was discussed and the effects of process parameters on the weld properties were evaluated. Major parameters involved in this process were plunge depth (PD), dwell time, joining time, and tool rotational speed. A successful friction joint of carbon fiber-reinforced poly composite laminate (CF-PPS)-metal was formed with an interlayer film of additional polyphenylene sulfide. In addition, a detailed overview of the friction techniques was discussed, such as friction stir spot welding (FSSW), friction stir welding (FSW), and refill friction stir spot welding (RFSSW). In this current work, we had focused on the parameters, process, and their development during friction welding of similar and dissimilar metals with CFRP joint. Regarding the FSSW review, the best tensile shear load was 7.1 kN obtained from AA5182 and CFRP at a rotational speed of 3,000 rpm and 5 s welding time. The thickness for AA5182 and CFRP are 1.2 and 3 mm, respectively. The most efficient parameters are rotational speed, PD, dwell time, and shoulder penetration depth. In addition, the heat generated during the process parameters, its influence on mechanical and microstructure properties along with the possible defects and internal cracks of the similar and dissimilar welded joints will be reviewed and discussed.

Evaluating the dynamic‐mechanical and thermal stability of polyphenylene sulfide composites filled with magnetic filler for sensor applications

AbstractIsotropic polyphenylene sulfide (PPS) composites filled with the magnetic fillers strontium ferrites (SrFeO) and neodymium iron boron (NdFeB) at two concentrations of 52 vol.% and 60 vol.% were prepared by the injection molding technique without use of an external magnetic field. Frequency sweeps shows that the mechanical frequency has little influence on the strength of all PPS samples and only ensures a higher mobility of the PPS chain ends at high frequency. Increasing the magnetic filler content and the use of NdFeB instead of SrFeO provide the PPS composites a larger structural robustness making them more resistant to mechanical loads and mechanically more stable. The temperature behavior of the PPS composites shows independently of the filler a strong softening from 80 °C. Nevertheless, larger operating temperatures below the glass transition temperature appear realistic.

Thermal Aging Effects on the Mechanical Behavior of Glass-Fiber-Reinforced Polyphenylene Sulfide Composites.

In this article, the thermal aging behavior of polyphenylene sulfide (PPS) composites, reinforced by 20% glass fibers (GFs), in thermal aging temperatures ranging from 85 to 145 °C was studied. Tensile and bending properties and color changes in the thermally aged samples were investigated. The results showed that thermal aging at this temperature range resulted in the degradation of mechanical properties. Both the tensile and flexural strength of the GF/PPS composites were significantly reduced after thermal aging at 145 °C. Decreased strength and brittle fracture were observed because thermal aging at high temperatures resulted in the deterioration of the interfaces between the GFs and PPS matrix. The degradation of the mechanical properties of the composite samples can be reflected by the color change, which means that the mechanical properties of the GF/PPS composite samples under thermal aging are predictable using color change analysis.

Polyphenylene sulfide fabric with enhanced oxidation resistance and hydrophobicity through polybenzoxazine surface coating for emission control in harsh environment

Emissions from power generation and municipal waste incineration sources are primarily at high temperatures and contain corrosive gases, particulate pollutants and are enormously challenging on the performance of the filtration systems in use. Here, polyphenylene sulfide (PPS) nonwoven fabric, a primary material used commercially in such settings, is modified with a polybenzoxazine precursor as a coating to deliver improved thermal and oxidation resistance to the fibrous substrate. The polybenzoxazine precursor undergoes chain propagation and crosslinking upon the treatment process to provide a protective layer over the PPS fibers such that enhanced structural stability in a harsh environment was demonstrated. We have shown the improved overall tensile strength (+15%), Young’s modulus (+26%), and more hydrophobic nature of the modified PPS fabric, while the superior environmental stability and better filtration performance could be achieved. Such methodology may lead to higher service temperature and extended service time of the PPS filtration bags in harsh fire exhaustion airstreams encountered in power plants or municipal garbage incineration facilities. The crosslinkable benzoxazine could also be the most cost-effective high temperature coating layer on fibers, enabling future high-performance air filtration materials.

A novel composite protective coating with UV and corrosion resistance: Load floating and self-cleaning performance

The research in functional materials has been the focus in studying industrial applications, particularly in the field of superhydrophobic functional bionic material. Although many studies of superhydrophobic surfaces have been published at this stage, the performance remain unsatisfactory, especially in a variety of harsh environments in practical applications, such as extremely cold weather, acidic or alkaline environment, prolonged exposure to light, high temperature, or oily wastewater, etc. The mechanical strength and corrosion resistance of coatings in such environments are all mighty challenges. In this study, we propose a fluoro silane-modified zinc oxide (FAS-ZnO) as a nano-filler. A superhydrophobic and oleophobic composite coating was successfully prepared through a single step by spraying suspensions containing attapulgite (ATP), FAS-ZnO, and carboxylated polyphenylene sulfide (PPS–COOH) onto desired substrates. In addition, stearic acid was added as a binder and used to enhance the bonding strength between the filler and the substrate. The composite coatings were characterized by FE-SEM, XRD and FT-IR on substrates, and the corrosion resistance of the coatings was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray chamber experiments. The composite coatings showed excellent corrosion resistance due to the synergistic effect of FAS-ZnO and ATP. It was found that the composite coating had good hydrophobic and oleophobic contact angles of 161 ± 1.5° and 159 ± 1°, respectively, which were mainly attributed to the construction of nano-scale structures. It is worth noting that the composite coating performed excellently in chemical stability, self-cleaning performance, UV resistance, anti-fouling function, mechanical strength, and load-bearing floating ability. The coating maintained its highly hydrophobic surface after being stretched through a universal testing machine. Based on the multiple key properties in the composite coating, it can be expected to be applied to large equipment and instrument surfaces in extreme outdoor environments.

The Effect of Surface Substrate Treatments on the Bonding Strength of Aluminium Inserts with Glass-Reinforced Poly(phenylene) Sulphide.

Materials composed of a polymer matrix reinforced with carbon/glass fibres providing lightweight and superior mechanical properties are widely used as structural components for automotive and aerospace applications. However, such parts need to be joined with various metal alloys to obtain better mechanical performance in many structural elements. Many studies have reported enhancements in polymer–metal bonding using adhesives, adhesive/rivet combined joints, and different surface treatments. This study investigated the influences of various surface treatments on the adhesion between glass-reinforced poly(phenylene) sulphide (PPS) and aluminium alloy during the injection over-moulding process. Adhesion strength was evaluated via the shear test. Correlations for the shear strength of the polymer–metal with different metal–substrate treatments were studied. Since the strongest bonding was attained in the treatment with the highest roughness, this value, as it determines the level of micromechanical interlocking of connected materials, seems to be a critical factor affecting the adhesion strength. Three-dimensional (3D) topographic images characterized with a 3D optical microscope indicated that there was a meaningful influence exerted by the interface topologies of the aluminium substrates used for the over-moulding process. The results further indicated that increases in a substrate’s surface energy in connection with atmospheric plasma treatments negatively influence the final level of the bonding mechanism.

In Situ Strain Distribution Measurement of Polyphenylene Sulfide-Aluminum Injection-Molded Direct Joints Using Synchrotron Radiation Microbeam X-ray Diffraction

Abstract The joining of dissimilar materials such as resin and metal has been attracting attention as a means of reducing the weight of automobiles. It is necessary to ensure that the dissimilar material joints are sufficiently strong and durable over time for practical use. Additionally, it is necessary to clarify the mechanisms that produce these properties. We fabricated direct joints of glass fiber-reinforced polyphenylene sulfide (GFRP) and unreinforced pure polyphenylene sulfide (PurePPS) that were injection molded onto aluminum (Al) with nanometer-scale surface irregularities. We used synchrotron microbeam X-ray diffraction to visualize the residual strain distribution at the jointed interface in a nondestructive, micrometer-resolution manner. While the GFRP-Al joint has a lower average tensile residual strain than the PurePPS-Al joint, its strain distributions are quite different. The residual strain distribution of the GFRP-Al joint was comparable to the orientation of glass fibers. The change in the strain distribution when tensile loading was applied in the elastic region was measured, indicating that the tensile strain at the jointed interface increased for PurePPS-Al. Our in situ microbeam X-ray diffraction method helps evaluate the strain at the interface, which is related to joint reliability.

Thermal and Crystallization Behaviour of Polyphenylene Sulfide in Engineering Polymer Blends with HDPE

Abstract The thermal and crystallization behaviour of polyphenylene sulfide (PPS) in its blends with high density polyethylene (HDPE) is reported. Three grades of HDPE ranging in MFI from 0.4 to 52 were used in the investigation. The effect of composition and molecular weight of HDPE on the crystallization process and morphology of PPS in the blends has been investigated by the technique of Differential Scanning Calorimetry (DSC). In the blends, PPS crystallizes in presence of molten HDPE. It is observed that the morphology of PPS in terms of crystallite size and crystallite size distribution in the blends is significantly affected by blending with HDPE. The temperature onset of melting was found to increase with increasing HDPE content and the melting peak width was found to decrease with increasing HDPE content. This indicates a larger crystallite size and a narrower crystallite size distribution of PPS in blends. The effect is more pronounced in HDPE-rich compositions. The extent of the variation in the temperature onset of melting and peak width were comparable for all the grades of HDPE. The degree of crystallinity of PPS in the blends is reduced significantly (55–70%) in HDPE-rich blends. Therefore, it is concluded that the crystallization of PPS is affected by the presence of HDPE melt. The crystallization scans of PPS in the blends, obtained in the cooling mode, did not show any evidence of accelerated nucleation. On the other hand, a marginal reduction in the temperature onset of crystallization was observed. The temperature range of crystallization of PPS in the blends was found to be less for all compositions except for 90/10 (PPS/HDPE). In summary it is concluded that blending of HDPE with PPS influences the crystal growth of PPS significantly although the effect on its homogeneous nucleation is also considerable. As a result, the morphology of PPS crystallized in blends is different from that of the homopolymer. The changes in the morphology of PPS are not sensitive to the molecular weight of HDPE probably because of the high temperature of PPS crystallization relative to the melting point of HDPE.

Improving the Performance of Perovskite Solar Cells with Insulating Additive-Modified Hole Transport Layers.

Invert perovskite solar cells (PSCs) present a great potential for next-generation photovoltaics for their flexibility and tandem adaptability. In order to improve the conductivity of the hole transport layer (HTL), such as poly(triarylamine), highly conductive additives (e.g., F4TCNQ, Li-TFSI) were generally applied to achieve a power conversion efficiency (PCE) exceeding 21%. However, these additives significantly affect the long-term stability of the devices due to their humidity sensitivity. In this work, the HTL was counterintuitively optimized with insulating additives, such as polyphenylene sulfide, which enhanced PCE from 19.1 to 21.5% along with a noticeable improvement in device stability with T50 of 574 h under double 85 aging conditions. The performance enhancement is attributed to larger grain sizes in perovskite films on the HTL and better energy-level alignment between the HTL and perovskite after introducing the insulating additives, which compensate negative influence caused by additive-induced reduction in conductivity. Our work demonstrates that low-conductivity additives, rather than the commonly used high-conductivity counterparts, can also contribute to improving the photovoltaic performance in PSCs.

Novel thermomechanical characterization for shrinkage evolution of unidirectional semi-crystalline thermoplastic prepregs (PPS/CF) in melt, rubbery and glassy states

Shrinkages, distortions and high residual stresses in the thermoplastic composite parts are induced due to high processing temperature, anisotropy, and fiber–matrix shrinkage mismatch. In this paper the shrinkages have been investigated experimentally and modeled by thermo-mechanical constitutive equations for PolyPhenylene Sulfide (PPS) and the unidirectional Carbon Fiber (PPS/CF) composite prepreg. The thermal shrinkage and the crystallization shrinkage were retrieved from Thermal Mechanical Analysis and compared to a Pressure specific volume Temperature diagram. To describe the crystallization shrinkage in the cooling process accurately, the crystallization kinetics of PPS was evaluated using Differential Scanning Calorimetry. The temperature-dependent elastic modulus was measured by a shear rheometer to formulate a new constitutive model. The mathematical model for shrinkage was validated by a press consolidated [0]12 laminate and unbalanced laminates in four lay-ups. The thermo-mechanical model results presented here provide significant rules for the thermomechanical and shrinkage predictions for the industrial applications of thermoplastic composite.

Polyphenylene sulfide scaffold based flexible supercapacitor electrode with competitive areal capacitance and flame-retardant behavior

Flexible supercapacitor electrode has been strongly developed as next-generation wearable energy storage electronics in the last decades. The state-of-the-art performance always requires the implantation of compelling energy-storage stuff and flexible scaffolds. However, the inflammable nature of such supercapacitors gives rise to safety issues, and it is a challenge to maintain high energy storage capability and flame-retardant behavior synergistically. Herein, we use a paper-making technique to engineer polyphenylene sulfide (PPS) ultrafine fibers and multi-walled carbon nanotubes (MWCNT), followed by the deposition of in-situ polymerization polypyrrole (PPy). This highly porous electrode exhibits a high areal capacitance of ~1650 mF cm−2 at a current density of 1 mA cm−2, and > 93% of capacitance retention after 5000 charging-discharging cycles at a current density of 20 mA cm−2. Notably, PPS/MWCNT/PPy electrode features noninflammability and zero generation of dense fume in the open flame. Also, the areal capacitance of the electrode remains more than 50% after 0.5 h annealing at 200 °C. This work delivers a new PPS scaffold-based supercapacitor electrode-manufacturing system directing at high energy-storage capability and harsh-environment adaptability.

Improvement of thermal and abrasion resistance performance of polyphenylene sulfide composite through 3-mercaptopropyl trimethoxysilane treatment of carbon fiber and graphene oxide fillers

The aim of this study was the improvement of the thermal conductivity and tribological properties of polyphenylene sulfide (PPS) with carbon fiber (CF) and graphene oxide (GO) fillers. Whereas CF reduce the mechanical strength of PPS, 3-mercaptopropyltrimethoxysilane (MPTMS)-treated CF improve the interfacial adhesion properties of fillers and PPS matrices, which increase the mechanical properties of composites. The improved thermal and mechanical properties of composites were confirmed via diffraction scanning calorimetry, dynamic mechanical analyzer, and wear test. The silane-modified PPS/20M-CF/5M-GO composite has a thermal conductivity of 0.323 W/m•K, which is 175% greater than that of the neat PPS composite. The friction coefficient has decreased from 0.236 to 0.176 and the specific wear rate has decreased from 1200 to 300 E−07 mm3/N•m.

Bristle worm inspired ultra-durable superhydrophobic coating with repairable microstructures and anti-corrosion/scaling properties

Superhydrophobic surfaces integrated with great water-repellency have been extensively studied while their practical applications are restrained by the infirm rough structures and poor chemical durability. In this study, an ultra-durable superhydrophobic polyphenylene sulfide (PPS) composite coating with repairable microstructures has been constructed by innovatively introducing the expandable graphite (EAG) and elastic fluororubber. Hydrophobic EAG@SiO2 nanoparticles synthesized by sol–gel and modified with perfluorodecyltrichlorosilane (PFTS) can expand to establish abundant micro/nanostructures for superhydrophobicity during the thermal treatment. Additionally, fluororubber powders as elastic micro-supports endows the surface structures with reversible deformation to resist the external mechanical damage. The prepared coating can restore its microstructures and superhydrophobicity even after 2000 abrasion cycles under a pressure of 125 kPa, exhibiting a fantastic mechanical durability. Moreover, the fabricated coating possessed good anti-corrosion and anti-scaling properties in high salinity oil/water emulsion due to the intrinsic oleophilicity of EAG@SiO2 and fluororubber, which can transform the surface shielding layer from fragile air film to stable oil film to impede scaling and corrosion mediums. Simultaneously, the prepared superhydrophobic coating also demonstrated outstanding self-cleaning and anti-fouling properties to prevent surface contamination by diatomite or glutinous slurry during outdoor application. Thus, this ultra-durable superhydrophobic coating with extraordinary repairable microstructures and anti-corrosion/scaling capabilities will be expected to open a new avenue to realize the large-scale applications of superhydrophobic coatings in harsh environments.