Poly Phenylene Oxide Research Articles

Transport properties of durable PANI/PPO composite membrane with interpenetrating layer

In this study, composite membranes based on polyphenylene oxide, polyaniline (as separation layer) and interpenetrating layer of polyphenylene oxide and polyaniline were prepared. It was demonstrated for the first time that the interpenetrating layer of polyphenylene oxide and polyaniline plays a crucial role in the transport and separation properties. Moreover, the preparation of such composite membranes is very simple and inexpensive. The composite membranes were characterized by TEM (to confirm the presence of interpenetrating layer), and IR and Raman spectroscopies (to confirm the deposition of polyaniline). The membranes simultaneously possess good transport properties and excellent separation coefficients for industrially interesting gases, such as: O2/N2 > 13, H2/CO2 > 8, CO2/CH4 > 110, H2/CH4 > 1000 and H2/N2 > 450. Importantly, the composite membranes have long-term stability: after 14 months the transport properties and separation coefficients had not changed, suggesting superior stability.

A comparative study on the rheological, thermal, and mechanical performance of epoxy resin modified with thermoplastics

Thermoplastics and functional polymers are commonly used modifiers for epoxy (EP) resin. In this study, an EP system was fabricated and modified with methyl methacrylate block copolymer (BMG), polyphenylene oxide (PPO) and polysulfone (PSF). This was carried out to study the influence of thermoplastic polymers and functional polymers on the properties of EP resins, and the performance of the different modified EP systems was studied and compared. The curing reaction, rheological performances, heat resistance, and mechanical properties of the EP blends were investigated. Curing process of EP resin was determined as 110 °C for 1 h and 150 °C for 3 h by using non-isothermal differential scanning calorimetry (DSC) method. The rheological test revealed that the EP/BMG and EP/PPO blends exhibited low viscosity and wide processing window compared to the EP/PSF blend, thereby indicating good processing performance. The thermal stability of the modified EP blends was evaluated by using dynamic mechanical analysis methods. The results showed that the glass transition temperature (Tg ) of EP/BMG, EP/PPO and EP/PSF blends were 123 °C, 129 °C, and 131 °C, respectively. BMG showed an excellent toughening effect on EP resin compared to PPO and PSF. In addition, the flexural strength and impact strength of EP/BMG were 114 MPa and 21.2 kJ/m2, respectively. The influence of polymers on the properties of EP resin stems from their molecular structures.

The Charring Effect and Flame Retardant Properties of Thermoplastic Elastomers Composites Applied for Cable

The halogen-free flame retardant (HFFR) thermoplastic elastomers (TPEs) composites filled with aluminum hypophosphite had been prepared by twin-screw extruder. The flame retardancy, thermal stability, charring-effect, mechanical and rheological properties of TPE composites had been investigated by cone calorimeter, limiting oxygen index (LOI), UL-94 (vertical flame) test, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), ultimate tensile and rheometer. The research results indicated that the flame retardancy and thermal stability of flame retardant (FR) TPEs had been dramatically improved. Obvious char-forming effect can be found for the samples with the addition of polyphenylene oxide (PPO) during high heat flow conditions, which presented more content and more compact of residue compared to the samples without PPO after combustion of cone calorimeter. Mechanical and rheological characteristics showed that the tensile strength and processability can be well maintained for FR TPEs composites, which was very important for industrial applications.

The Evaluation of the Hemocompatibility of Polymer Membrane Materials for Blood Oxygenation

A comprehensive interdisciplinary study is performed for 12 polymers promising for the fabrication of membranes for extracorporeal membrane oxygenation based on them by methods of gas permeability, wetting, piezoelectric microweighing, and direct biomedical methods for determining hemocompatibility of whole blood from healthy donors. It is found that trimethylsilyl-substituted polytricyclononene, polyhexafluoropropylene, and semicrystalline polyphenylene oxide are the best polymer materials for the diffusion membranes of oxygenators. It is shown that traditional approaches that associate the surface properties of polymers (water wettability, plasma protein adsorption, energy characteristics of surfaces) with their hemocompatibility do not provide precise correlations with the biomedical methods based on the analysis of the changes in the shape of blood cells as a result of adhesion on the surface of the polymer. The complexity of the mechanism of interaction of the surface of polymers with blood also does not allow for clear structure–property correlations traditional for membrane gas separation. The directions of further research in this area are defined.

Performance Study of Membrane Capacitive Deionization (MCDI) Cell Constructed with Nafion and Aminated Polyphenylene Oxide (APPO)

Performance Study of Membrane Capacitive Deionization (MCDI) Cell Constructed with Nafion and Aminated Polyphenylene Oxide (APPO)

Surface modified and gradation-mixed Al2O3 as an effective filler for the polyphenylene oxide (PPO) insulative layer in copper clad laminates

Although filling ceramic powders into the insulative polymer layer has long been realized as an effective strategy to elevate the heat dissipation capability and service life of copper clad laminates (CCLs), the weak interfacial bonding between inorganic filler and organic matrix and the discontinuous thermal conductive network have hindered such beneficial effects. Herein, the silane coupling agent (KH-560) modified and gradation mixed Al2O3 served as an effective filler for CCLs. After optimization of the filling scheme through tremendous efforts, the maximum thermal conductivity of corresponding CCLs with surface modified and gradation-filled Al2O3 achieved to 0.646 W/m·K, apparently higher than that of pure resin CCLs (0.291 W/m·K) and single-size Al2O3 filled CCLs (Al2O3-20 μm-50%, 0.573 W/m·K). Simultaneously, the peel strength and bending strength of the CCLs with the surface modified and graded-mixed Al2O3 kept at a satisfactory level (0.903 N/mm and 306 MPa, respectively), surpassing those of CCLs with pristine Al2O3 fillers. In addition, the dielectric loss reduced to 4.67 × 10–3 and the water absorption was as low as 0.364%. Such a comprehensive performance could be ascribed to the improved interfacial bonding brought by KH-560 and a more contiguous heat conduction network formed by the gradation-filled Al2O3. This study offers a new strategy promising for high speed and high frequency applications of CCLs with so many alternative ceramic fillers.

Influences of high‐impact polystyrene loading on the foaming behavior andflame‐retardantproperties of polyphenylene oxide composites blown withCO2

AbstractPolymeric foam with high expansion ratio, well‐defined cell structure, and excellent flame retardant properties is essential for broadening its applications. Polyphenylene oxide (PPO) is a kind of cost‐effective engineering plastic with excellent flame retardancy, anti‐dripping behavior, and good mechanical strength, but suffers from its poor processability. In this study, microcellular PPO composite foams were fabricated by applying a solid‐state foaming technology using compressed CO2as the blowing agent. High‐impact polystyrene (HIPS) phase was introduced with the aim to improve the fluidity and foaming ability of PPO composites. It was interesting to find that the 18–48% HIPS loading significantly increased the expansion ratio, that is, 1.8–3.3 versus, 10.8–14.3, and broadened the optimum foaming temperature of PPO composite foams, attributing to the miscible character between PPO and HIPS and excellent foaming ability of HIPS. Furthermore, the as‐prepared PPO/HIPS composite foams exhibited high limited oxygen index (LOI) of 22.0–29.9%, low horizontal flammability rate (HFR) of 60.5–141.2 mm/min, and anti‐dripping behavior, and the void fraction was verified to be a critical parameter to determine the flame retardant performance of the composite foam. Besides its lightweight and excellent flame retardant properties, PPO composite foams also presented uncompromised tensile properties and well‐defined thermal insulation properties.

Novel crosslinked brominated polyphenylene oxide composite nanofiltration membranes with organic solvent permeability and swelling property

：Organic solvent nanofiltration (OSN) membranes have gained increasing attention for their wide applications in organic phase system. However, the fabrication method rather than the swelling behavior receives more attention during the OSN testing. In this work, a thin-film composite membrane with an internal cross-linking network by reacting 4,4-bipyridine with brominated poly (2,6-dimethyl-1, 4-phenylene oxide) (BPPO) has been prepared for organic solvent nanofiltration (OSN). The bipyridine groups substituted on the polyphenylene oxide polymer backbone act as cross-linkers and cationic channels for remarkable chemical stability and high solvent permeability. The permeability of the cross-linked BPPO (CBPPO) thin-film membranes exhibited high related to the viscosity and solubility parameter of solvents. The stability of CBPPO membrane was studied via various organic solvent immersing experiments. The result demonstrated that the composite membrane swelling changed to an extent of no more than 2.01%. It can be attributed to the low conformational flexibility of polymer chains with a high crosslinking degree. The ethanol permeation and dye rejection were compared before and after soaking. The calculation of the MWCO and membrane potential of modified CBPPO membranes showed that the swelling behavior of the CBPPO composite membranes is mainly affected by the membrane charge densities rather than the pore size.

Migration of surrogate contaminants from paperboard to foods: Effect of food and surrogate properties

ABSTRACT The current research describes an alternative test method to evaluate the impact of food properties and compound characteristics on migration from paperboard to food. Tightly sealed bottles containing paperboard spiked with surrogate components as a donor, together with modified polyphenylene oxide (MPPO or Tenax®) or one of the nine considered foods as a receptor, were stored at 22°C. Instead of analysing the receptor, migration from donor to receptor was followed up by evaluating the recovery of surrogates from the donor over time, thus avoiding challenges in the analysis of the foods as such. Free fat content affected the migration more than the specific surface area of the food, reaching a plateau at fat contents >8.1%. The highest migration was observed to fatty foods such as biscuits (8% to 25% fat) and chocolate (40% fat). Intermediate migration occurred to starchy and particulate foods such as egg-based wheat pasta (2.6% fat), wheat flour (1% fat) and rice flour (0.5% fat). Low migration occurred in the case of paperboard in contact with wheat pasta (0.4% fat). Native starch was found to be more sensitive to migration than gelatinised starch. Volatility was identified as the most important characteristic of the migrating compounds. MPPO was considered as a suitable surrogate for dry foods as it did not underestimate migration in any case. However, for low-fat foods such as wheat pasta, clear overestimations could occur, but only for volatile surrogates with vapour pressure over 1.45 mTorr.

Investigation on preparation and properties of novel polyphenylene oxide based composites by injection molding

A novel category of polyphenylene oxide (PPO) based composites loading with different volume fractions (0, 5, 20, 35, 50 vol%) of Mg2SiO4–MgTiO3 (MSMT) ceramics was prepared by injection molding. The results showed that PPO/MSMT composites with dense microstructure and uniform filler distribution were obtained. With the increase of MSMT ceramics from 0 to 50vol%, the dielectric constant of the composite increased from 2.65 to 5.00 while the dielectric loss of it decreased significantly from 4.1 × 10−3 to 2.0 × 10−3 at 10 GHz. Increasing the testing frequency from 1 GHz to 14 GHz had little effect on the dielectric constant, but led to gradually deteriorating of dielectric loss from 1.2 × 10−3 to 2.3 × 10−3 when 35vol% MSMT ceramics were loaded. Additionally, the coefficient of thermal expansion of the PPO/MSMT composite was reduced remarkably from 76.4ppm/°C to 33.2 ppm/°C. The flexural strength of the PPO/MSMT composites is increased from 98.90 to 114.39 MPa. The novel PPO/MSMT composites prepared by injection molding process possessed excellent comprehensive properties, which are expected to be important candidates for high-frequency application in electronic packaging fields.

Interlaminar Fracture Toughness of Carbon-Fiber-Reinforced Epoxy Composites Toughened by Poly(phenylene oxide) Particles

In this study, carbon fiber reinforced epoxy composites were interleaved by polyphenylene oxide (PPO) particles to improve their delamination resistance. The morphology of PPO particles at the inte...

Dual‐phase polyphenylene oxide membranes with copolyimide branched modifiers

AbstractPoly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) membranes are attractive due to high permeability for gases; however, the selectivity of these membranes is insufficient. In this work, the gas selectivity was improved without significant loss of the permeability. For this purpose, PPO was modified via incorporation of the branched copolyimide filler–grafted copolyimide (PI‐g‐PMMA) with polymethyl methacrylate (PMMA) side chains. Two series of mixed self‐supporting PPO/PI‐g‐PMMA films (with variation of the filler content) were prepared and studied as gas separation membranes. The length of the polymide (PI) chain and the density of PMMA grafting were the same in both series, however, in one series the grafted chains contained 50 MMA units, and in the other 150 units. The intermolecular interactions between the PPO matrix and the PI‐g‐PMMA fillers were investigated using viscometry, infrared (IR) spectroscopy, and scanning electron microscopy. The compatibility of the polymer components is limited; however, for both series, the contents of the respective filler are found, which ensures phase segregation only in a microscale. Therefore, the mechanical properties of the films allow their use as gas separation membranes. It is shown that the degree of the segregation as well as the mechanical and gas transport properties of the membranes depend on the length of the PMMA chains, and the membranes with filler‐containing shorter branches (50 MMA units) show better selectivity.

Plasticization- and aging-resistant membranes with venation-like architecture for efficient carbon capture

Plasticization and physical aging due to the undesirable deformation of chain microstructure under high pressure or long-term operation hamper the practical application of polymer membranes. Fixing the polymer chain architecture without sacrificing the internal free volume and thereby the membrane permeability remains a grand challenge. The venation architecture in plant leaf, featured by its stable vein structure with abundant interveinal spaces, offers us an inspiration for designing a highly permeable and stable chain architecture. Here, we construct a venation-like chain architecture in polyphenylene oxide (PPO) membrane by introducing numerous interchain crosslinking bridges using Friedel-Crafts-based hypercrosslinking reaction. These crosslinking bridges rigidify the chains and prevent them from dense packing, inhibiting the microstructural deformation, while simultaneously generating abundant free volume. The resulting membranes display ultrahigh CO2 permeability of 5130 Barrer (73-fold higher than pristine PPO membrane), along with superior structural stability. Particularly, the plasticization is fully suppressed under high pressure even up to 70 bar and the physical aging-induced loss of CO2 permeability is reduced remarkably down to as low as 19% after 360 days, transcending most of the state-of-the-art membranes. This venation-like chain architecture opens a new avenue to solving the current permeability-stability dilemma for the implementation of polymer membrane technology.

Separation and recovery of materials from the waste light emitting diode (LED) modules by solvent method

Nowadays, a large quantity of Light Emitting Diodes (LEDs) have been produced and updated with the development of optoelectronic industry. At the same time, many waste LEDs are discarded. However, there are many metals and non-metals in waste LEDs, which may cause secondary pollution and waste of resources if disposed improperly. In this study, solvent method was used to dissociate the waste LED modules and recycle resources. Firstly, the components of the waste LED modules were analyzed. The main component of the transparent plastic part, usually used as packaging materials, is cured epoxy resin, and the main component of the white plastic part as the skeleton of LED modules is a mixture of polyphenylene oxide (PPO) and polystyrene (PS). Then, eight organic solvents, [EMIM+]BF4− ion liquid and sodium hydroxide (NaOH) inorganic reagent were tried to separate a 40 × 40 mm2 waste LED module respectively. The results showed that only three organic solvents—dimethylformamide (DMF), dimethylacetamide (DMA), dimethyl-sulfoxide (DMSO) could dissociate the waste LED module very well. The used DMF solution was purified by rotary evaporation, and the regenerative DMF solution could be reused because its property has not changed. The solid residue obtained after rotary evaporating DMF was identified as polystyrene (PS). It was inferred that the waste LED module was dissociated through the DMF dissolving the PS of white plastic. In addition, the effect of DMF, DMA and DMSO dissociating the waste LED modules with the change of temperature was discussed. It was found that the choice of suitable solvent is a key for this method, and the heating temperature was also a very important factor. Finally, it was measured that the cured epoxy resin and the white plastic of the waste LED module accounted for about 31.4% (w/w) and 37.7% (w/w) respectively, which can be recycled. In short, the method not only separated completely the waste LED module and its each part was recycled easily, but the solvents can be reused. This study suggests a new route to recycle LEDs due to its environmentally friendly process, which may exert a significantly beneficial impact on our environment.

Study on the char-forming and synergistic flame retardant performance of SEBS/HIPS/PPO composites applied for cable

ABSTRACTThe halogen-free flame retardant (HFFR) styrene-ethylene-butylene-styrene (SEBS)/high impact polystyrene (HIPS)/polyphenylene oxide (PPO) composites filled with aluminium hypophosphite (AHP) and melamine cyanurate (MCA) had been prepared. The thermal stability, flame retardancy, carbon slag structure, mechanical and rheological properties of SEBS/HIPS/PPO composites had been investigated. The research results showed that the thermal stability and flame retardancy of SEBS/HIPS/PPO composites were significantly improved, and there was obvious intumescent FR (IFR) synergism between AHP and MCA. Meanwhile, the role of AHP and MCA in char-forming promotion and carbon slag enhancement was also an important reason. Scanning electron microscopic (SEM) images showed that the char residual structure of sample A-4 showed more compact than that of A-3 which was similar to agglomerated loose sand, and that of A-2 presented an intumescent structure of twisted flake carbon slag after combustion of cone calorimeter. The ultimate tensile strength increased slightly because of the addition of PPO.

Designing Anion Exchange Membranes with Enhanced Hydroxide Ion Conductivity by Mesoscale Simulations

This work studied polyphenylene oxide tetramethylammonium (PPO-TMA) anion exchange membrane by dissipative particle dynamics (DPD) simulations. The simulation method is validated by semiquantitativ...

Enhancement of alkaline conductivity and chemical stability of quaternized poly(2,6-dimethyl-1,4-phenylene oxide) alkaline electrolyte membrane by mild temperature benzyl bromination.

A series of quaternized polyphenylene oxide (QPPO) based alkaline electrolyte membranes with different degrees of quaternization were synthesized via a benzyl bromination method at mild temperature (75 °C). Quite a high hydroxide conductivity under the reduced water uptake and swelling was exhibited by this method. When the degree of bromination measured from 1H NMR analysis was 30%, the corresponding hydroxide ion conductivity was 0.021 S cm−1. The chemical stability of the QPPO membranes was excellent, showing only 3% weight loss in 3 M NaOH solution during 1 month. The fuel cell performance test under H2/O2 exhibited the power density of 77 mW cm−2 and the current density of 190 mA cm−2 at 70 °C. Such excellent properties of QPPO membranes resulted from the achievement of the quaternization at the benzyl position, specifically.

Biodegradation of plastic monomer 2,6-dimethylphenol by Mycobacterium neoaurum B5-4

2,6-Dimethylphenol (2,6-DMP), an important chemical intermediate and the monomer of plastic polyphenylene oxide, is widely used in chemical and plastics industry. However, the pollution problem of 2,6-DMP residues is becoming increasingly serious, which is harmful to some aquatic animals. Microbial degradation provided an effective approach to eliminate DMPs in nature, which is considered as a prospective way to remediate DMPs-contaminated environments. But the 2,6-DMP-degrading bacteria is not available and the molecular mechanism of 2,6-DMP degradation is unclear as well. Here, a 2,6-DMP-degrading bacterium named B5-4 was isolated and identified as Mycobacterium neoaurum. M. neoaurum B5-4 could utilize 2,6-DMP as the sole carbon source for growth. Furthermore, M. neoaurum B5-4 could degrade 2,6-DMP with concentrations ranging from 1 to 500 mg L−1. Six intermediate metabolites of 2,6-DMP were identified and a metabolic pathway of 2,6-DMP in M. neoaurum B5-4 was proposed, in which 2,6-DMP was initially converted to 2,6-dimethyl-hydroquinone and 2,6-dimethyl-3-hydroxy-hydroquinone by two consecutive hydroxylations at C-4 and γ position; 2,6-dimethyl-3-hydroxy-hydroquinone was then subjected to aromatic ring ortho-cleavage to produce 2,4-dimethyl-3-hydroxymuconic acid, which was further transformed to citraconate, and subsequently into TCA cycle. In addition, toxicity bioassay of 2,6-DMP in water using zebrafish indicates that 2,6-DMP is toxic to zebrafish and M. neoaurum B5-4 could effectively eliminate 2,6-DMP in water to protect zebrafish from 2,6-DMP-induced death. This work provides a potential strain for bioremediation of 2,6-DMP-contaminated environments and lays a foundation for elucidating the molecular mechanism and genetic determinants of 2,6-DMP degradation.

Improved Processing and Properties for Polyphenylene Oxide Modified by Diallyl Orthophthalate Prepolymer.

Diallyl orthophthalate (DAOP) prepolymer was investigated as a reactive plasticizer to improve the processability of thermoplastics. The rheology of blends of DAOP prepolymer initiated by 2,3-dimethyl-2,3-diphenylbutane (DMDPB) and polyphenylene oxide (PPO) was monitored during the curing process, and their thermal properties and morphology in separated phases were also studied. Differential scanning calorimetry (DSC) results showed that the cure degree of the reactively plasticized DAOP prepolymer was reduced with increasing PPO due to the dilution effect. The increasing amount of the DAOP prepolymer led to a gradual decrease in the viscosity of the blends and the rheology behavior was consistent with the chemical gelation of DAOP prepolymer in blends. This indicated that the addition of the DAOP prepolymer effectively improved processability. The phase separation occurring during curing of the blend and the transition from the static to dynamic mode significantly influences the development of the morphology of the blend corresponding to limited evolution of the conversion around the gel point.

Styrene-terminated polyphenylene oxide and polybutadiene low dielectric reactive blend

Styrene-terminated polyphenylene oxide (SPPO) and low polar thermosetting polybutadiene (PB) resin were employed to obtain a curing system with excellent electrical properties and enhanced thermal properties. By terminal styrenisation, SPPO is cured with PB, forming a continuous phase in the blend. The SPPO/PB blends have excellent solvent resistance and thermal stability, while the good dielectric performance is retained. Especially, when the mass ratio of PB is 0.5, the curing system has a high Tg of 226.5°C and excellent dielectric properties with Dk = 2.46 and Df = 0.0022 at 10 GHz, which is suitable for high frequency electrical applications.