PPS Composites Research Articles

On the thermo-visco-elastic behaviour of neat and aged PPS composites

Reinforced PPS thermoplastics exposed to variations in temperature and humidity are subject to aging and interface degradation. These phenomena can lead to ruptures due to the interphase weakening. In this study, a micromechanical model based on the equivalent inclusion model is implemented using the viscoelastic behaviours of the neat and aged grades identified by spectrometric analyses. The presented coated inclusion model allows to extract the viscoelastic behavior of the interphase in the dry-as-molded composite and in the aged composite by inverse method conducted for viscoelastic behavior. The presence of the interphase testifies to the degradation of the thermomechanical properties in the vicinity of the reinforcements. In the aged composite, the interphase also undergoes an aging phenomenon. Thus, the model compares the behavior of the interphase in the dry-as-molded and aged grades of the composite and separates the effects linked to the degradation of adhesion of the fibers from the effects linked to specific hydroscopic aging.

Effect of Cooling Temperature on Crystalline Behavior of Polyphenylene Sulfide/Glass Fiber Composites.

Poly (phenylene sulfide) (PPS) is a super engineering plastic that has not only excellent rigidity and high chemical resistance but also excellent electrical insulation properties; therefore, it can be applied as an electronic cover or an overheating prevention component. This plastic has been extensively applied in the manufacture of capacitor housing as, in addition to being a functional and lightweight material, it has a safety feature that can block the electrical connection between the electrolyte inside and outside the capacitor. Moreover, the fabrication of PPS composites with high glass fiber (GF) content facilitates the development of lightweight and excellent future materials, which widens the scope of the application of this polymer. However, the crystallinity and mechanical properties of PPS/GF composites have been found to vary depending on the cooling temperature. Although extensive studies have been conducted on the influence of cooling temperature on the crystalline behavior of PPS-based composites, there has been limited research focused particularly on PPS/GF composites for capacitor housing applications. In this study, to apply PPS/GF composites as film capacitor housings, specimens were prepared via injection molding at different cooling temperatures to investigate the composites' tensile, flexural, and impact energy absorption properties resulting in increases in mechanical properties at high cooling mold temperature. Fracture surface analysis was also performed on the fractured specimens after the impact test to confirm the orientation of the GF and the shape of the micropores. Finally, the crystallinity of the composites increased with higher cooling temperatures due to the extended crystallization time.

Novel Use of Cellulose Based Biodegradable Nano Crystals in the Machining of PPS Composites: An Approach Towards Green Machining

Because of their biodegradable and regenerative properties, cellulose nanocrystals derived primarily from naturally occurring cellulose fibers serve as a sustainable and environmentally beneficial material for most applications. Although these nanocrystals are inherently hydrophilic, they can be surface functionalized to suit a wide range of demanding requirements, such as those associated with the creation of high-performance nanocomposites in hydrophobic polymer matrices. Therefore, the present work deals with the application of cellulose-based biodegradable nanocrystals as a lubricant in the machining of PPS composites. In this study, milling process was considered to investigate the influence of the sustainable lubricating conditions on the machinability indexes of PPS composites. As a novel cooling approach, water-based solutions enriched by cellulose nanocrystals with different reinforcements (0.25%, 0.5%, and 1%) were used over known methods such as MQL, conventional flood, and dry. According to the research outcomes, cellulose nanocrystals-based nanofluids provided satisfying contributions on retarding the tool wear and reducing the cutting temperatures considerably. Despite the surface-related results such as roughness, topography and texture are promising for the developed strategy; further investigations will be useful to determine ideal water-particle concentration to improve the quality of the machined surface.

Enhanced mechanical, tribological, and acoustical behavior of polyphenylene sulfide composites reinforced with zero‐dimensional alumina

AbstractPolyphenylene sulfide (PPS) is a semicrystalline thermoplastic which can pass UL94V‐0 standard without adding flame retardant. In the present study, effect of alumina (Al2O3) addition on the mechanical, tribological, and acoustical behavior of PPS polymer were investigated. Experimental findings indicate that elastic modulus, tensile strength, and flexural strength were enhanced by 21.4%, 7.7%, and 6.9%, respectively. The highest tensile strength was obtained when PPS was reinforced with 5 wt% Al2O3 while highest bending strength and toughness were obtained with 20 wt% Al2O3. Reinforced composites encountered <5% and <14% mass loss when heated to 420 and 500°C, respectively. Lower filler concentrations (<5 wt%) had insignificant effect on the glass transition temperature (Tg) of the composite. Experimental results agreed well to Hashin–Shtrikman and Suquet predictions at lower filler concentrations since filler particles could be easily dispersed in the interstitial sites of PPS matrix without significant agglomeration. Besides, significant acoustic emission (AE) characteristic such as higher absolute energy rate was witnessed in Al2O3 reinforced PPS composites. The insights derived from this study are expected to open a new avenue of producing composites with high stiffness, strength, and significant AE events by using zero‐dimensional fillers.

Insights into the luminescent properties of poly(phenylene sulfide)-grafted metal-organic framework (Tb–MOF–PPS) copolymers

In this study, a novel poly(phenylene sulfide)-grafted metal-organic framework (Tb–MOF–PPS) was fabricated. Initially, 2,5-dichloroterephthalic acid and TbCl3·6H2O were used as raw materials to synthesize the dihalogenated MOF (Tb–MOF) through ultrasound irradiation and hydrothermal methods. Subsequently, Tb–MOF was added at different mole proportions (2.5, 5, 7.5, and 10%) for the copolymerization of PPS, and a serial of Tb–MOF–PPS composites were successfully obtained. Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy proved that the Tb–MOF was covalently connected to PPS. The introduction of the Tb–MOF had no evident influence on the thermal properties of the composites. Additionally, the fluorescence characteristics revealed that the fluorescence excitation and emission spectra of the composites had a large redshift compared with that of PPS and possessed visible-light photoluminescence properties. These results indicate that the composites obtained can be used as optical sensors.

Tribological characterisation of polymer composites for hydropower bearings: Experimentally developed versus commercial materials

To mitigate the effects of downstream lubricant spillage from hydroelectric power plants, environmentally friendly lubricants are required. For the sustainable operation of oil-free bearings, the development of high performance bearing materials is crucial. In this study, the tribological performance of PPS and UHMWPE-based composites, incorporating various reinforcements, such as graphene oxide, is evaluated and compared with five commercial materials. Experiments were performed under different lubricating conditions; Dry, water, and using a glycerol-based environmentally adaptive lubricant (EAL). The use of water inhibited an adequate transfer film, which increased wear for most materials. EAL lubrication showed a significant reduction in friction (up to 98%) when compared to dry conditions. The experimentally developed PPS composite provided superior tribological properties, especially under water-lubricated conditions.

Thermal aging performance of glass fiber/polyphenylene sulfide composites in high temperature

AbstractIn order to use the glass fiber reinforced polyphenylene sulfide composites (GF/PPS) in high temperature environments, thermal aging performance of two kinds of commercial grade PPS composites, reinforced by 40% glass fiber, PPS‐G40 HM and 1140L4, in thermal aging temperature of 250°C was compared by tensile strength, oxidized layer, color, crystallization and melting behavior. The results showed that tensile strength of GF/PPS composites is significantly decreased with increasing of aging time below 200 h and the tensile strength of aged PPS‐G40 HM is higher than that of aged 1140L4. The thickness of dark color area is increased with increasing of aging time. The thickness of oxidized layer of 1140L4 is thinner than that of PPS‐G40 HM. However, the color of oxidized layer of PPS‐G40 HM is lighter than that of 1140L4. The recrystallization in thermal aging results in the formation of crystal with higher melting point and increased melting temperature of GF/PPS composites. It is found that addition of epoxy resin can increase the initial mechanical property and improve the thermal aging performance of GF/PPS composites. A novel modified GF/PPS composite with higher thermal aging properties was obtained.

Static and fatigue behavior of injection molded short-fiber reinforced PPS composites: Fiber content and high temperature effects

Two different short glass fiber reinforced PPS composites with different fibers content (30% and 40% in weight) were tested upon static and fatigue loading at room temperature. The material with 40% fiber content was also tested at high temperature (160 °C) both in static and fatigue condition. All the specimens were injection molded directly in standardized dog-bone geometry without further cutting or machining. Static tests at three different displacement rates were performed in order to calculate the main static mechanical properties and to observe the strain-rate sensitivity. Fatigue tests for both materials were performed in load control with 0.1 load ratio. The S-N curves are presented in semi-logarithmic coordinates. Some derived cyclic parameters such as the cyclic mean strain and cyclic modulus were calculated to observe the capability to describe the input test variables effect on the damage mechanism. The fracture location distribution along the specimen longitudinal axis were observed and the transverse cross-sections were analyzed by means of optical microscopy in order to correlate the micro-structure and the mechanical properties.

Thermal and mechanical behavior of graphene loaded synthetic graphite/polyphenylene sulfide (PPS) composites

Thermoplastics when they become thermally conductive, have a great potential to be used in thermal management applications due to their low cost, lightweight, and flexibility. Here, synthetic graphite and graphene are used as thermally conductive fillers to fabricate Polyphenylene Sulfide- (PPS) based composite materials with high thermal conductivity. Graphene and graphite added PPS composites were manufactured by using a twinscrew extruder and injection molding machine. Physical, thermal, mechanical, and morphological properties of the composites were investigated by several characterization methods including thermogravimetric analysis, differential scanning calorimetry, thermomechanical analysis, scanning electron microscopy, thermal diffusivity measurement, and tensile and flexural tests, The in-plane and through-plane thermal conductivity coefficient of graphene (5 wt. %) loaded synthetic graphite (40 wt. %)/PPS composites are greatly improved to 26.45 and 5.02 W/mK, respectively compared to that of neat PPS. The outstanding in-plane thermal conductivity of graphene loaded graphite/PPS composites is attributed to the formation of an effective thermal conductive pathway due to the alignment of the layered structure of graphene and graphite fillers in the flow direction.

Significantly enhanced structural integrity of adhesively bonded PPS and PEEK composite joints by rapidly UV-irradiating the substrates

A high-power UV-irradiation technique was proposed for the surface treatment of PPS and PEEK composites, aiming to achieve good adhesion with epoxy adhesives. The composite substrates were rapidly UV-irradiated for a duration of between 2–30s, and then bonded using an aerospace film adhesive to produce joints. Tensile lap-shear strength and mode-I and mode-II fracture energies of the adhesive joints were investigated. It was observed that the application of a short-time UV-irradiation to the substrates transformed the failure mode of the specimens from adhesion failure to substrate damage in all cases. This consequently resulted in remarkable improvements in the mechanical and fracture performance of the adhesive joints. For example, the lap-shear strength increased from 11.8MPa to 31.7MPa upon UV-irradiating the PPS composites for 3s, and from 8.3MPa to 37.3MPa by applying a 5s UV-irradiation to the PEEK composites. Moreover, the mode-I and mode-II fracture energies significantly increased from ∼50J/m2 to ∼1500J/m2 and from <300J/m2 to ∼7000J/m2, respectively for both of the adhesively bonded PEEK and PPS composite joints.

Co-cure joining of epoxy composites with rapidly UV-irradiated PEEK and PPS composites to achieve high structural integrity

Efficient joining of hybrid thermoset/thermoplastic composite joints is critical to produce high performance lightweight structures while keeping the cost low. Herein, a high-power UV-irradiation technique was proposed to rapidly active the surfaces of PEEK and PPS composites for the following co-cure joining with epoxy composites. A single lap-shear joint test and a double cantilever beam test were used to evaluate the mechanical and fracture performance of the hybrid joints. The experimental results revealed that high structural integrity of the hybrid joints was achieved upon applying a 6 s UV-treatment to the thermoplastic composites. For example, the lap-shear strength and fracture energy of the adhesive bonded hybrid joints were above 25 MPa and 800 J/m2, respectively. Overall, high-power UV-irradiation proved a highly efficient, rapid and low-cost method to treat thermoplastic composites for the co-cure joining with epoxy composites, and hence it demonstrated significant promise in industrial mass production.

Co-cure joining of epoxy composites with rapidly UV-irradiated PEEK and PPS composites to achieve high structural integrity

Co-cure joining of epoxy composites with rapidly UV-irradiated PEEK and PPS composites to achieve high structural integrity

Overlapped repair performance for carbon–PPS composites in vacuum-assisted thermal bonding

An overlapped repair with a continuous bonding area, was applied to carbon–PPS thermoplastic composites, and their strength recovery rate and failure behavior under mechanical loading were analyzed. This overlapped model has been designed to prevent the common and fundamental failures in conventional repair technologies through utilization of the volume fraction properties of continuous fibers. The same material was used for the parent and repair, and adhesion occurred via reversible thermal properties of the thermoplastic PPS polymer, without using additional adhesives. Under tensile and flexural loading, thickness ratios of 30% and 50% (damaged depth to the total thickness of the laminate) resulted in high strength recovery rates of 96% and 94%, respectively. The overlapped, bonded area on the surface of the parent material is the path of external load transfer between the parent and repair materials, maintaining uniform stress dispersion and increasing the fracture resistance.

Influence of temperature and cooling liquid immersion on the mechanical behavior of a PPS composite: experimental study and constitutive equations

This paper presents an experimental and theoretical study conducted on a PolyPhenylene Sulfide with 40 wt.% of short glass fibers (PPS GF40) and its matrix. Widely used for under-the-hood applications in the automotive industry, this material is subjected to high temperatures and to the ageing effects of the cooling liquids. Therefore, the consideration of those conditions is essential to design mechanical parts. Thus, an experimental campaign in the tensile mode was carried out at different temperatures and for various glycol proportions in the cooling liquid, under monotonic and cyclic loadings on neat and reinforced PPS. The results of these tests enabled us to highlight some of the main physical phenomena occurring during these experiments under tough hydrothermal conditions. Following this analysis, a visco-elasto-pseudo-viscoplastic model is proposed. Moreover, this model enables the consideration of the effects of the cooling liquid and its constituents using a temperature/humidity equivalence. This model also takes into account the consequences of the glass transition on the mechanical behavior of the material. Its accuracy was confronted to that of an artificial-intelligence-based model, so as to know what the physically possible maximum accuracy is. Finally, the evolution of the model parameters was studied with the adjunction of short glass fibers and for various orientation distributions of those fibers.

Multiscale thermal study of virgin and aged polyphenylene sulfide reinforced by glass fiber

AbstractIn this study, virgin and thermal aged PPS samples were prepared and tested using different techniques such as thermogravimetric analysis (TGA), coupled TGA–Fourier transform infrared spectroscopy (FTIR), and FTIR as well as optical microscopy. Some interesting research results can be summarized as follows: TGA results prove the PPS composite samples aged at 180 and 200°C have been degraded obviously during the aging period in oven. Moreover, accelerated aging leads to the degradation of PPS composite with the observation of increased thermal oxidation layer from outside to inside. There is a plateau standing at about 350 μm for the thermal oxidation layer at oxidation temperature of 200°C. Some thermal decomposition models are applied to clarify the degradation kinetics of PPS composite. According to the activation energy value, it appears degradation more easily at the beginning of the heating process in the atmosphere of oxygen than that of nitrogen. Moreover, the related products of PPS composites during pyrolysis are fully discussed with the combined analysis of TGA–FTIR techniques.

Preparation of nano-SiO2 compound antioxidant and its antioxidant effect on polyphenylene sulfide

Abstract Polyphenylene sulfide (PPS) is easily oxidized at high temperature, which greatly limits its applications. In this study, a nano-SiO2 compound antioxidant (SiO2-g-AO) was prepared and incorporated into PPS by melt compounding to obtain PPS/SiO2-g-AO composites. SiO2-g-AO was prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl) (antioxidant AO) with an aminosilane coupling agent (KH792). Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) confirmed that the antioxidant AO was successfully immobilized on the surface of SiO2 and the thermal stability was improved. Scanning electron microscopy (SEM) images showed that SiO2-g-AO was uniformly dispersed in PPS. It has been found that the crystallinity and mechanical properties of PPS composites improved, and the dynamic oxidation induction temperature (OIT) increased in the range of 16.7°C–21.1°C. A synergistic anti-oxidation model of nanoparticles and antioxidants, namely a multi-stage antioxidant system, was established by comprehensive analysis of experimental results. The synergistic anti-oxidation model provides a new idea for the antioxidant modification of polymer composites.

Compressive and flexural behavior of carbon fiber-reinforced PPS composites at elevated temperature

ABSTRACTThe effect of temperature on the mechanical behavior of carbon fiber reinforced polyphenylenesulfide (PPS) composites was investigated by compressive and flexural tests from ambient temperature up to 150°C. The failure morphologies of the C/PPS composites were analyzed to identify the variation of failure modes. Related results showed that the mechanical behavior of C/PPS composites decreased severely with the increase of temperature due to the softening of matrix. The PPS resin film tensile test was carried out and the PPS matrix behavior was recognized as the main factor to dominate the mechanical behavior of composites under compressive/flexural loading at elevated temperatures. It can be found that there was an approximate linear relationship between the compression properties of C/PPS composites and the PPS matrix. The dependence of failure modes of composites on temperatures was closely related to the mechanical behavior of PPS matrix.

Mathematical description of mechanical behavior of woven fabric reinforced PPS‐based composites at high temperature

Carbon fiber fabric reinforced PPS (C/PPS) composites exhibit significant nonlinearity before failure, particularly with respect to shear deformations. Loading‐unloading Iosipescu shear tests for the composites at different high temperatures are conducted. It is found that there exist significant plasticity deformations and stiffness degradation. A one‐parameter damage‐plasticity model is proposed to describe mathematically the nonlinear mechanical behavior of the C/PPS composites at high temperatures. The relationship between effective stress and effective plastic strain in a power form, the evolution of damage in an exponential form and the shear modulus are all associated with temperature. It is verified that the proposed model can well characterize the shear and off‐axis compressive nonlinear behavior of the composites at different temperatures. POLYM. COMPOS., 40:1097–1103, 2019. © 2018 Society of Plastics Engineers

Effects of Covalent Functionalization of MWCNTs on the Thermal Properties and Non-Isothermal Crystallization Behaviors of PPS Composites.

In this study, a PPS/MWCNTs composite was prepared with poly(phenylene sulfide) (PPS), as well as pristine and covalent functionalized multi-walled carbon nanotubes (MWCNTs) via melt-blending techniques. Moreover, the dispersion of the MWCNTs on the PPS matrix was improved by covalent functionalization as can be seen from a Field-Emission Scanning Electron Microscope (FE-SEM) images. The thermal properties of the PPS/MWCNTs composites were characterized using a thermal conductivity analyzer, and a differential scanning calorimeter (DSC). To analyze the crystallization behavior of polymers under conditions similar with those in industry, the non-isothermal crystallization behaviors of the PPS/MWCNTs composites were confirmed using various kinetic equations, such as the modified Avrami equation and Avrami-Ozawa combined equation. The crystallization rate of PPS/1 wt % pristine MWCNTs composite (PPSP1) was faster because of the intrinsic nucleation effect of the MWCNTs. However, the crystallization rates of the composites containing covalently-functionalized MWCNTs were slower than PPSP1 because of the destruction of the MWCNTs graphitic structure via covalent functionalization. Furthermore, the activation energies calculated by Kissinger’s method were consistently decreased by covalent functionalization.

자동차 전조등 광원 모듈용 유리섬유강화 PPS 복합재료 특성 연구

자동차 전조등 광원 모듈용 유리섬유강화 PPS 복합재료 특성 연구