Poly Aryl Sulfone Research Articles

Polyaryl sulfone amine oxide membranes with adjustable pore and interesting “trade-off” effect

Creating advanced polymer membranes with adjustable pores for various separation methods has been challenging because of the lack of new materials with adaptable and reversible chemical structures. In this study, we designed membranes using polyarylene ether sulfone/amide tertiary amine (PAES/ATA) copolymerized with polyarylene ether sulfone and polyamide tertiary amine. These membranes incorporated amine oxide units into their molecular chains by oxidizing the TA unit in the PAES/ATA copolymer chain. Applying the oxidation process improved antifouling properties, with the oxidized membrane showing a permeance recovery rate (Frr) of 95.48 % and a total fouling ratio (Rt) of 9.35 %. These units also functioned as switches, altering their charge in different pH environments, thereby allowing pore size adjustment in the membranes. Notably, with the formation of amine oxide, these membranes exhibited properties distinct from the traditional “trade-off” effect, which is a persistent challenge in membrane technology development. The permeance and rejection rate of these membranes demonstrated the “simultaneous rise phenomenon” following a facile oxidation treatment to form amine oxide. This study presents a novel approach to develop membranes with new functional and tunable filtration capabilities, potentially applicable in various separation processes.

The effects of laser line energy on welding strength of PASF/PC using magnesium zinc alloy powders as absorbents in laser transmission welding

The metal powder absorbents have the advantage of fabricating clean and high-strength joints in the process of laser transmission welding dissimilar transparent thermoplastics. However, the joining behavior between metal powders and thermoplastics is vague. Herein, polyarylsulfone (PASF) and polycarbonate (PC) are selected as model materials to investigate the joining behavior using magnesium zinc alloy (MZA) powders at different laser line energies. The shear force test was performed to reveal the effect of laser line energy on the welding. The µ-CT images reveal the evaluation of welding strength is attributed to the specific joint morphology. The multi-scale morphology characterization shows that the fractured surface height increases with increasing the laser line energy. The voids between MZA powders and resins increase the risks of interface failure, and the bubbles in the resins increase the risks of cohesion failure. The effects of laser line energy on the joint characteristics are elaborated based on the thermo-physical property test and transient temperature field analysis. The above results indicate the optimized welding temperature locates the melting temperature of PASF, because of the good fusion of PASF and less decomposition of PC. The study can provide a guideline for choosing proper process parameters when choosing metal powders as laser absorbents in welding dissimilar transparent thermoplastics.

The Numerical Simulation of Welding Residual Stress of Dissimilar Transparent Thermoplastics with MZA Powder Absorbent

Abstracts: There are residual stresses in the joint caused by swift temperature variation in the process of laser transmission welding with metal absorbent. However, the related forming process is hard to detect through experimental methods. Herein, a physical model is established to describe the evolution of stress during the welding of polyarylsulfone (PASF) and polycarbonate (PC). The evolution of heat stress and the forming of residual stress is analyzed through the method of heat-force sequential coupling. In this process, the condensate transition, metal powder deformation, and clamping forces are involved in the mathematical model of stress-strain. In this model, the stress history can be divided into n time intervals according to the principle of superimposed stresses. The results revealed a significant correlation between the thermal history and stress evolution. Furthermore, the maximum von-mises stress appeared at the time of 1.7 s, then there was a decreasing tendency and stabled at 9 s. The von-mises stress was considered as residual stress after that time and the related stress distribution was investigated. The findings of this study provide a comprehensive understanding of residual stress on the joint.

Mechanism and factor analysis of welding PC and PASF using magnesium zinc alloy particles as laser-absorbent

Effectively joining dissimilar transparent thermoplastics plays an important role in lightweight design in vehicles and automotive industry. However, their different physical–chemical properties hamper the welding of thermoplastics directly with diode laser. In this study, magnesium zinc alloy particles (MZAP) are chosen as laser-absorbent to join polycarbonate (PC) and polyarylsulfone (PASF) specimens. First, the comparison of PC/PASF weldments with different laser-absorbents was performed, including adding carbon black (CB) as laser-absorbents. The morphology and mechani-cal properties show the weldments prepared with MZAP have advantages of cleaner appearance and stronger shear strength. Furthermore, the fracture surface and joint microstructure reveal that the mechanical riveting structure, composed of defused MZAP and filled thermoplastics in the gaps between adjacent MZAP, forms when the MZAP was used as laser-absorbent. Comparing with CB aggregates, the fused MZAP has a stronger ability to resist external force and leads to a higher shear strength. Finally, the analysis of factors of MZAP feature reveals that the mechanical riveting structure contributes to improving the shear strength, the defects, such as creaks, holes and bubbles should be eliminated in the welding. The results of analysis of variance illustrated the particle size and the standoff distance are statistically significant for the shear strength. This study provides a potential avenue to effective weld dissimilar thermoplastics.

The rheology of ultra-high molecular weight poly(ethylene oxide) dispersed in a low molecular weight carrier.

Gel spinning is the industrial method of choice for combining hydrophilic ultra-high molecular weight (UHMW) polymer resins with a hydrophobic support polymer to produce composite filaments for cytapheresis. Cytapheresis is a medical technique for removal of leukocytes from blood. Gel spinning is used to avoid high melt viscosity and thermal sensitivity of UHMW resins and the high melt temperature of the substrate resin but requires the recovery of toxic solvents. The UHMW resin is used because it forms a stable gel phase in the presence of water; a lower molecular weight resin (LMW) simply dissolves. UHMW and LMW resins were both poly(ethylene oxide) (PEO) and the substrate was polyarylsulfone (PAS). The literature indicated PEO undergoes non-oxidative thermal degradation above 200 °C and PAS is processed up to 350 °C. Dynamic oscillatory shear rheometry was used to study 0, 25, 40, 50, 60, and 75 wt. % UHMW PEO in LMW PEO to take advantage of the sensitivity of viscosity to changes in molecular weight and material configuration, indicating degradation. Samples were exposed to 220 °C, 230 °C, 240 °C, 250 °C, 275 °C, and 300 °C temperatures for 5 min to explore conditions that could result in sample degradation. The viscosity decreased less with increasing UHMW PEO content for samples exposed to the same temperature and the viscosity decreased more with increasing exposure temperature for samples with the same UHMW PEO content. Parameters were regressed from observed data to predict the change in molecular weight via empiricisms relating the viscosity to molecular weight, shear rate, temperature, and time.

Laser transmission welding of Polyarylsulfone using zinc particles absorber

Polyarylsulfone (PASF) has excellent features of heat resistant and mechanical performance, however it is difficult to be welded by laser directly because of the perfect light transmittance. Zinc particles with carbon black (ZPCB) as laser absorbers were used to weld PASF plates. The effects of processing parameters, laser power (P) and welding speed (v), on the interface structure and welding strength were investigated. Morphological analysis was performed in order to evaluate the composition of the fracture surface and the longitudinal section of the welded samples. The element distribution and chemical composition on the fracture surface were analyzed with X-ray photoelectron spectroscopy (XPS). A physical model was established to illustrate the change of bonding interface structure before and after the welding.

Developing toughened aromatic polybenzoxazines using thermoplastic oligomers and telechelics, part 1: Preparation and characterization of the functionalized oligomers

ABSTRACTThe preparation and characterization of three families of thermoplastic oligomers (Mn = 2918–13263 g mol−1) based on polyarylsulfone (PSU) differing in both molecular weight and terminal functionality and one series of polyarylethersulfone (PES) of different molecular weights is reported. Infrared and nuclear magnetic resonance spectroscopy data support the formation of both the hydroxyl terminated oligomers and conversion (67–89% depending on molecular weight) to the telechelic PSU oligomer bearing reactive benzoxazine groups. Differential scanning calorimetry reveals that the onset of homopolymerization in the telechelic PSU oligomer occurs at around 100°C (peak maximum 125°C at 10 K/min) and rescans show values of the glass transition (for the homopolymers) ranging from 124 to 167°C depending on molecular weight. The influence on the oligomer backbone and terminal functionality is examined using thermal analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40875.

Toughening Mechanisms in Aromatic Polybenzoxazines Using Thermoplastic Oligomers and Telechelics

2,2-Bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine)propane (BA-a) is blended with oligomers of polyarylsulfone (PSU) and polyarylethersulfone (PES) of different low/intermediate molecular weights (3000–12 000 g mol–1) and terminal functionality (chloro-, hydroxyl- or benzoxazinyl- (Bz)). Fracture toughness (KIC) is observed to increase from 0.8 MPa m0.5 for cured BA-a to 1 MPa m0.5 with the incorporation of 10 wt % PSU-Bz (12 000 g mol–1). Generally, greater improvements in KIC are observed for the PES oligomers compared with the PSU oligomers of equivalent molecular weight. The terminal functionality of the thermoplastic has a lesser effect on improving toughness than increasing the molecular weight or the nature of the polymer backbone. Surface analysis of the fractured surfaces show greater phase separation and crack pinning in the PES toughened system. Where crack pinning is less obvious, as in the case of hydroxyl-terminated PES (of 6000 g mol–1), this coincides with a drop in fracture toughness.

Cytotoxic effects exerted by polyarylsulfone dialyser membranes depend on different sterilization processes

Polyarylsulfone group is one of the most important polymeric materials used in the biomedical field, due to its excellent properties, such as good thermal, chemical, and mechanical stability. There are three important polyarylsulfone polymers, all of which have excellent electrical properties: polysulfone (PSu), polyarylsulfone (PAS) and polyarylethersulfone (PAES). All these polymers have excellent creep, radiation and high temperature resistance. In this study, we aimed to determine the effect of three sterilization processes (steam, ethylene oxide and gamma rays) on cytotoxicity of polyarylsulfone dialysis membranes. Ten long-term dialysis patients and ten age-matched healthy controls were enrolled in our study. We analysed (1) serum effect on cultured endothelial cell viability using MTT assay and (2) lipid peroxidation assessed by serum malondialdehyde (MDA) formation at the beginning (T0), the middle (T2) and the end (T4) of haemodialysis (HD) session. Our results clearly showed that steam-sterilized membranes improve endothelial cell viability when compared to ethylene oxide or gamma rays-sterilized ones. Moreover, there is a increased generation of MDA in patients sera during HD session. The serum MDA concentration was about 3, 6 and 10 times higher, respectively, for steam, ethylene oxide and gamma rays sterilization procedures when compared to the MDA amount in healthy subject sera. We concluded that using steam instead of ethylene oxide or gamma rays for sterilization may improve the biocompatibility of polyarylsulfone membranes.

Rheological Behavior of Polyarylsulfone 1‐Butyl‐3‐Methylimidazolium Chloride Solutions

Polyarylsufone polymers are engineering thermoplastics that can only be dissolved in polar solvents. We found that polyarylsufone has good solubility in ionic liquid (IL) with IL being a new kind of green solvent; thus, ILs are potential substitutes for conventional molecular solvents. However, the thermodynamics in ionic liquids are different then those in conventional solvents, so ILs as solvents have attracted enormous attention recently. Rheological behavior is an important factor in polymer material processing. The rheological behavior of polyarylsulfone (PASF) in both N, N,‐dimethylacetamide (DMAc) and ionic liquid 1‐butyl‐3‐methylimidazolium chloride [(Bmim) Cl] were studied in this paper as a function of concentration for concentrated solutions. It is interesting that the rheological behavior of the PASF/(Bmim) Cl solution is very different from that of PASF/DMAc solutions. In DMAc, as concentration increases viscosity increases, while the rheological behavior of the PASF/(Bmim) Cl solution exhibits a maximum in the viscosity‐concentration plots.

A Laser Ionization Time-of-Flight Mass Spectrometric Study of UV Laser Ablation of Polyarylsulfone Films

Neutral fragments from the 248 nm laser ablation of polyarylsulfone (PAS) were investigated using laser post ionization (193 nm) time-of-flight (TOF) mass spectroscopy. Three regimes of ablation fluence were distinguished with respect to detected fragments and differences in their velocity distributions. Over the entire fluence range the arrival profiles of the products matched with a shifted Maxwell-Boltzmann distribution. Interestingly, average translational velocities revealed a non-monotonical dependency on ablation fluence. This is probably be due to screening effects of the ablation pulse by the plume, or to non-thermal effects that may contribute to the ablation process at high fluences. The dependencies of both the flight velocities and the Knudsen layer temperature of the fragments on fluence suggest that PAS ablation is photothermally driven. However, the excessively high values for average translational energies (up to 34 eV at high fluences) and their increases with increasing fragments amu indicate that the process also has some non-thermal features.

Laser ablation mechanism and plume dynamics of polyarylsulfone films studied by laser ionization time-of-flight mass spectrometry

The KrF laser ablation of polyarylsulfone (PAS) was investigated for fluences between 90 and 200 mJ/cm2. Neutral fragments were probed using laser post ionization (193 nm) time-of-flight (TOF) mass spectrometry. Decomposition of PAS was found to occur mainly through scission of C-S and C-O bonds as well as via decomposition of the phenylene rings in the chain. The dependencies of both the flight velocities and the Knudsen layer temperature of the fragments on fluence suggest that PAS ablation is a photothermal process. In contrast, the high average translational energies (up to a few tens of eV) indicate the existence of a non-thermal component in the process. In terms of the plume dynamics, the fitting of the arrival profiles of the fragments with a shifted Maxwell–Boltzmann distribution over the full fluence range indicates the existence of a collision during the adiabatic expansion process.

Blends of a thermotropic liquid crystalline polymer and some flexible chain polymers and the determination of the polymer-polymer interaction parameter of the two polymers

Blends of a thermotropic liquid crystalline polymer (LCP) with poly(ether imide) (PEI), poly(ether ether ketone) (PEEK), polysulfone (PSF) and polyarylsulfone (PAS) prepared by screw extrusion have been investigated by differential scanning calorimeter and dynamic mechanical thermal analysis. From the measured glass transition temperature (T g ) and specific heat increment (ΔC p ) at the T g , it appears that the LCP dissolves more in the PEI- and PEEK-rich phases than does the PEI and PEEK in the LCP-rich phase. From the DSC study of PSF-LCP and PAS-LCP blends, the T g (PSF) and T g (PAS) of each blends are almost constant with blend composition. Therefore, it is concluded that PSF and PAS are immiscible with LCP. The polymer-polymer interaction parameter (X 12 ) and the degree of disorder (y/x 1 ) of LCP have been investigated using the Flory lattice theory in which the anisotropy of LCP is considered. The X 12 values have been calculated from the T g data and found to be 0.181±0.004 at 593 K for the PEI-LCP blends and 0.069±0.006 at 623 K for the PEEK-LCP blends. Using the previously presented method, the X 12 and y/x 1 in partially miscible systems have been determined.

Energy Absorption Behavior of Carbon-Fiber-Reinforced Thermoplastic Composite Tubes

The primary objective of this work was to study the energy absorption characteristics of carbon-fiber-reinforced thermoplastic composite tubes. Composite tubes with different thermoplastic matrices-polyetheretherketone (PEEK), polyetherimide (PEI), polyimide (PI), and polyarylsulfone (PAS) -have been investigated. Fiber orientations of 0°,±5°±10°, ±15°, ±20°, ±25° and ±30° with respect to the axis of the tube were used. Among the thermoplastic tubes investigated, the carbon fiber/PEEK tubes displayed the highest specific energy absorption capability. This was attributed to the superior fracture toughness of the carbon fiber/PEEK composite material and a large number of frond splits and fractured fibers in the crush zone. The specific energy absorption capability was dependent on the fiber orientation. Efforts have been made to relate the change in specific energy to the variation of microfracture processes in the crush zone.

The relationship between structure and deformation behavior of sulfone polymers

AbstractThe deformation of three types of sulfone polymers—polysulfone (PSF), poly(ether sulfone) (PESF), and polyarylsulfone (PASF)—was performed with a mechanical testing system (MTS). The result and samples were studied using a transmission electron microscope (TEM), a dynamic mechanical analyzer (DMA), and a dielectric thermal analyzer (DETA). Stripes on TEM micrographs for small deformations increase with the fracture toughness (GIc). The activation energy (Ea) of the α‐transition was determined from DETA. The results show that both Ea and TEM micrographs can be used to qualitatively estimate the order of GIc of sulfone polymers. An energy model was proposed to explain this phenomenon.

Controlled release herbicide formulations based on polymeric microspheres

A series of polymeric microsphere formulations were prepared and tested for their ability to control the release of an herbicide, Dicamba (DA; 3,6-dichloro-2-methoxybenzoic acid). Microspheres (MSs) were produced from ethyl cellulose (EtCell), polyarylsulfone (PS), or a combination of the two, in the desired size range of 20–40 μm by solvent evaporation or spray drying. Generally, PS MSs could be loaded with more DA (up to nearly 50 wt%) than could the EtCell MSs (maximum loading obtained was 23 wt%). EtCell MSs released DA at a greater rate than did comparable PS MSs under sonication and soil column irrigation release tests. The release rate of DA from the EtCell MSs could be controlled by using different viscosity grades (i.e., molecular weights) of EtCell: higher viscosity EtCell led to a lower DA release rate. The release rate of DA from MSs was also controlled by using a combination of EtCell with PS. Overall, MSs prepared from EtCell, PS or EtCell/PS show promise as controlled release formulations for herbicides.

Melt Rheology of Some Specialty Polymers

Speciality engineering thermoplastics are steadily gaining importance in a wide variety of high temperature applications due to their excellent performance char acteristics at elevated temperatures. A knowledge of the rheological behaviour of these speciality polymers over an industrially relevant range of shear rate and temperature is essential m the design of polymer processing equipment, process optimization and trouble-shooting. A method proposed earlier has been extended to estimate the complete flow curves for some of the important speciality poly mers such as polyphenylene oxide, polyphenylene sulfide, polyether sulfone, polyaryl sulfone, polyether ether ketone, polyetherimide and polyarylates, through the use of the developed grade- and temperature-independent unified curves along with the appropriate melt flow index value. The master curves have been fitted by appropriate rheological models and then using a single integral constitutive equation of the BKZ type the unified normal stress difference curves have been predicted. These unified normal stress difference curves would be useful for determining the elastic flow parameters for the speciality polymer melts merely from the knowledge of the melt flow index.

Flash-Fire Propensity of Plastics and Elastomers

Various plastics and elastomers were evaluated for flash-fire propensity, using the USF flash-fire screening test method. The test results were compared with those obtained with the NBS and Douglas test methods. Polyurethane flexible foams were among the materials exhibiting the greatest flash-fire propensity in all three tests, and polychloroprene flexible foams were among the materials exhibiting the least flash-fire pro pensity in the USF and Douglas tests. The materials that appeared to be the least prone to flash fires included polyvinyl chloride, polyphenylene oxide and sulfide, polyether and polyaryl sulfone, and polychloroprene, polyphosphazene, and silicone flexible foams.

Thermochemical characterization of some thermally stable thermoplastic and thermoset polymers

AbstractThe thermochemical and flammability properties of some thermally stable polymers considered for use in aircraft interiors are described. The properties studied include: (a) thermomechanical properties such as glass transition and melt temperature; (b) dynamic thermogravimetric analysis in anaerobic environment; (c) flammability properties such as oxygen index, flame spread and smoke evolution; and (d) selected physical properties. The thermoplastic polymers evaluated included polyphenylene sulfide, polyaryl sulfone, 9,9‐bis(4‐hydroxyphenyl)‐fluorene polycarbonate‐poly(dimethylsiloxane) and polyether sulfone. The thermoset polymers evaluated included epoxy, bismaleimide, a modified phenolic and polyaromatic melamine resin. These resins were primarily used in the fabrication of glass reinforced prepregs for the construction of experimental panels. Test results and relative rankings of some of the flammability parameters are presented and the relationship of the molecular structure, char yield, and flammability properties of these polymers are discussed.

Assessment of relative flammability and thermochemical properties of some thermoplastic materials

AbstractThe thermochemical and flammability characteristics of some typical thermoplastic materials currently in use and others being considered for use in aircraft interiors are described. The properties studied included (a) thermal mechanical properties such as glass transition and melt temperature, (b) changes in polymer enthalpy by differential scanning calorimetry, (c) thermogravimetric analysis in an anaerobic and oxidative environment, (d) oxygen index, (e) smoke evolution, (f) relative toxicity of the volatile products of pyrolysis, and (g) selected physical properties. The generic polymers which were evaluated included: acrylonitrile‐butadiene‐styrene, bisphenol A polycarbonate, bisphenol fluorenone carbonate‐dimethylsiloxane block polymer, phenolphthalein‐bisphenol A polycarbonate, phenolphthalein polycarbonate, polyelher sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone; chlorinated poly vinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters including molding characteristics of some of the advanced polymers are described. Test results and relative rankings of some of the flam inability, smoke and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic or equivalent to polymers in current use. A relationship of the anaerobic char yield of the polymers to their relative flammability properties is shown.