Poly Ether Imide Blends Research Articles

Constructing a dual gradient structure of energy level gradient and concentration gradient to significantly improve the high-temperature energy storage performance of all organic composite dielectrics†

The severe electrical conduction loss at elevated temperature is the initial factor for the degradation of energy storage performance of polymer dielectric films, thus it urgently needs to develop highly heat-resistant polymer capacitive films for meeting the advancing electrical and electronic applications. For reducing conduction loss and improving the high-temperature energy storage performance of dielectrics, the current approaches are focusing on preventing carriers mobility at elevated temperature and high electric field. In this study, the molecular semiconductor ITIC (ITIC is an organic molecular semiconductor 2,2′-[[6,6,12,12-Tetrakis(4-hexylphenyl)-6,12-dihydrodithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene-2,8-diyl]bis [methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)]]bis[propanedinitrile] abbreviation) with high electron affinity was filled into the blends of polyether imide (PEI) and polyethersulfone (PESU). The energy level gradient was constructed due to the different energy bandgap structures among ITIC, PESU and PEI. In addition, the concentration structure gradient was constructed due to the concentration of ITIC which varies along the thickness direction. The results demonstrate that the dual gradients of energy level and concentration can effectively inhibit carrier migration and lower conduction loss, thus significantly improving the electric breakdown strength and energy storage performance at high temperature. The energy storage densities (Ue) of 5.14 J/cm3 and 3.6 J/cm3 at 150 °C and 200 °C, respectively were achieved in PEI/PESU blends with 9 layers of ITIC gradient and 0.25 % ITIC in the outer layer. This study puts forward a novel structural design combining the energy levels gradient with concentration gradient to optimise the high-temperature energy storage properties of all-organic dielectric films.

Development of microfiltration membranes based on polysulfone and polyetherimide blends.

In this study, membranes blended with polysulfone (PSU) and polyetherimide (PEI) polymers in different ratios were fabricated. Their potential to remove pollutants from rivers, which are a potential drinking water source, was investigated. Scanning electron microscopy analysis revealed that the PSU membranes had a dense and homogeneous layer, whereas the addition of PEI formed a spongy substrate. The water content of the fabricated membranes varied between 5.37 and 22.42%, porosities 28.73-89.36%, contact angles 69.18-85.81%, and average pure water fluxes 257.25-375.32 L/m2 h. The blended membranes removed turbidity, chloride, alkalinity, conductivity, sulfate, iron, manganese, and total organic carbon up to 98.32, 92.28, 96.87, 90.67, 99.58, 94.63, 97.48, and 79.11%, respectively. These results show that when PEI was added to the PSU polymer, the filtration efficiency increased owing to an increase in the hydrophilicity of the membranes. Blending these two polymers enabled the optimization of membrane properties such as permeability, selectivity, and mechanical strength. In addition, membrane fabrication processes are simple and incur low costs.

Hydrogen Bonding of Aramid Boosts High-Temperature Capacitive Properties of Polyetherimide Blends

Polyetherimide (PEI) is the state-of-the-art commercial high-temperature polymer dielectric with excellent thermal and chemical stability and relatively high high-temperature capacitive energy storage properties. The rotation of the dipoles in the PEI chains brings the β-relaxation which seriously increases the leakage current and decreases the charge-discharge efficiency. In this work, hydrogen bonds have been introduced to limit the dipole rotation of PEI by blending aramids [1,4-poly(ether fluoromethyl naphthalene amide), PNFA] into the PEI matrix. By introducing 10 wt % PNFA, the β-relaxation of the blend has been significantly reduced which could be observed from the dielectric spectrum. To explore the mechanism of limited β-relaxation, we analyze the hydrogen bonds in the blend films by infrared spectroscopy and found that the maximum content of hydrogen-bonded carbonyl formed between PNFA and PEI chains was 14.3% when the content of PNFA was 30 wt %. The content of hydrogen bonds formed between PNFA and PEI was positively correlated with the energy storage performance of the blends. The maximum discharged energy density with an efficiency above 90% of the blend film with 30 wt % PNFA reaches 4.1 J cm-3 at 150 °C, which is about 350% higher than that of pristine PEI. This work shows that composing hydrogen bonds by the blending method could be a viable strategy for enhancing the high-temperature energy storage performance of polymer dielectrics, which could be achieved by large-scale preparation and has feasible industrial production prospects.

Studies on miscibility of polyetherimide/polystyrene blends

The miscibility behavior of the blends of Polyetherimide (PEI) and P olystyrene (PS) was studied using different experimental techniques. The intrinsic viscosities were determined for different ratios of PEI/PS blend in dilute chloroform solutions at 25oC using viscometry. According to different methods proposed by Huggins, Krigbaum and Wall, Catsiff and Hewett using the experimental results of the intrinsic viscosity studies of the PEI/PS blends, some miscibility parameters were obtained. Besides, the miscibility of the PEI/PS blends was studied using Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry measurements.

Microstructural, thermal and rheological correlations to mechanical response of polyamide-6(glass filled)/polyetherimide blend: effect of ethylene-octene copolymer on toughening of blend

Melt mixed glass-filled polyamide 6(PA6)/polyetherimide (PEI) blends were prepared in a co-rotating twin screw extruder over the entire composition range of 0–100 wt% of polyamide 6. These blends were characterized by structural, rheological, mechanical and thermal properties. Crystallization behavior and phase morphology of the blends were also investigated. The blend with the composition PA6/PEI 75/25 showed overall improved mechanical properties along with low resultant viscosity which can be processed on standard equipment. Shear viscosity along with shear stress of the blends were analyzed using shear rheometer which concluded that the blends can be processed on standard equipment due to resultant low viscosity. Scanning electron microscope micrographs revealed that the morphology of the blends showed a two phase structure in which the minor phase was dispersed as domains in the continuous phase. Polyolefin elastomer (POE) as impact modifier was added to the above composition in the range of 0–15 phr to study its effect. The thermal characteristics of PA6, PEI, and PA6/PEI blends with and without POE were investigated using DSC and TGA which revealed that the melting temperature and crystallization temperature of the blend remained unchanged while XRD results showed percent crystallinity was increased slightly. Furthermore, it can be said that the blend with composition PA6/PEI 75/25 with 10 phr impact modifier loading was suitable for high end applications because it combines the high mechanical properties of glass-filled PA6 with inherent flame-retardant property of PEI while POE overcomes the physical weakness of moisture absorption.

Comparison of Ultem 9085 Used in Fused Deposition Modelling (FDM) with Polytherimide Blends.

Polyetherimide (PEI) blends modified by either polycarbonate (PC) or polyethylene terephthalate glycol-modified (PETG) were prepared. The latter modifier (PETG) was an industrial grade widely used for fused deposition modelling (FDM) printing. PEI blends were compared to Ultem 9085, which is the standard PEI grade for FDM printing in advanced applications. All the blends were thoroughly characterized in terms of their rheological, morphological, thermomechanical and tensile properties. Ultem 9085 showed improved rheology for processing over standard PEI. PEI/PC blends with 10 wt % of modifier developed here closely matched the viscosity behavior of Ultem 9085. On the other hand, the blends with low PC content (i.e., less than 20 wt %) outperformed Ultem 9085 in terms of thermal and tensile properties. When PETG was added, similar tensile properties to Ultem 9085 were found. The immiscibility for PC contents higher than 20 wt % deteriorated the tensile properties, making it less attractive for applications, although melt viscosity decreased further for increasing PC contents.

Reduced viscosity, rheology and morphological properties of sulfonated poly (ether ether ketone): Polyetherimide blends

Blends of poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared in five different weight ratios, using N, N-dimethylacetamide (DMAc) as solvent. Reduced viscosity and rheological parameters of these blends were investigated. Cannon–Fenske viscometer was used to study the viscoelastic parameters of the salt-free polyelectrolyte blends and the data obtained was fitted in Fuoss–Strauss equation. Effects of temperature and concentration have been investigated. It was observed that the storage modulus ( G′) and dynamic viscosity ( η′) of the blends varies significantly as compare to pure SPEEK and PEI. Surface morphology and thermal behavior of the membranes were studied using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Form SEM results it was observed that the phase separation occurs at 25% PEI contents in blends.

Kinetics of phase separation at the early stage of spinodal decomposition in epoxy resin modified with PEI blends

The behavior at the early stage of spinodal decomposition (SD) for polyetherimide (PEI)/epoxy blends was investigated. It was found that the phase separation of PEI/epoxy blends took place by SD mechanism. The development of molar mass in the epoxy resin was gradual and then the three blends could still be considered as concentrated solutions of thermoplastic. The kinetics at the early stage of phase separation for these blends could be described by the Cahn–Hilliard–Cook linearized theory.

Cellulose Acetate and Polyetherimide Blend Ultrafiltration Membranes, I: Preparation, Characterization, and Application

Ultrafiltration (UF) techniques have particular advantages for simultaneous purification, concentration, and fractionation of macromolecules. In this study, polymeric blend ultrafiltration membranes based on cellulose acetate and polyetherimide were prepared by phase inversion technique and characterized in terms of compaction time, pure water flux (PWF), water content, membrane hydraulic resistance, and scanning electron microscopy (SEM). The blend membranes prepared were subjected to the separation of macromolecular proteins such as bovine serum albumin (BSA), egg albumin (EA), pepsin, and trypsin. The molecular weight cut-off (MWCO) of blend membranes obtained from the protein separation studies is also presented. Toxic heavy metal ions such as copper, nickel, zinc, and cadmium were subjected to separation by the blend membranes by complexing them with the polymeric ligand polyethyleneimine. The separation and permeate flux efficiencies of the blend membranes are compared with those of pure cellulose acetate membranes.

Nanoporous Polymer Films from Immiscible Polymer Blends: Pore Size and Composition Dependence

ABSTRACTNanoporous polymer films have been prepared using immiscible blends of polyetherimide (PEI) and poly(caprolactone diol) (PCLD). The films were prepared by spin-coating from a common solvent — dichloromethane (DCM). To create the nanoporous films, PCLD was removed by immersing the films in acetone, which dissolves PCLD only. Field emission scanning electron microscopy was used to study the porous structure. The pore structure of the films was affected by many factors such as composition of the blend, molecular weight, and various processing parameters. The formation of nanometer size pores was mainly due to the fast phase separation process during spin-coating. The pore size and pore size distribution was found to depend on the blend composition.

Miscible blends of nitro‐substituted polybenzimidazole and polyetherimide

AbstractA novel blend system was prepared by blending organosoluble nitro‐substituted polybenzimidazole (NO2‐PBI) and polyetherimide (PEI) in a cosolvent at a moderate condition. It was shown that the NO2‐PBI/PEI blends not only possess tractable processability owing to the enhanced solubility of NO2‐PBI but also retain the desirable features of unmodified PBI/PEI blends. Apparent miscibility in the blends was observed and attributed to hydrogen‐bonding interactions between NH groups in NO2‐PBI and carbonyl groups in PEI. It was revealed that the NO2‐PBI/PEI blends phase‐separate upon heating above the glass‐transition temperatures. The observed mixing of NO2‐PBI and PEI in a molecular level, although sustainable only in the glassy region, was shown to lend synergy effects to the physical properties of the blends. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1778–1783, 2001

Intractable high-Tg thermoplastics processed with epoxy resin: Interfacial adhesion and mechanical properties of the cured blends

The intractable, high-temperature-resistant thermoplastics (TPs) polyphenylenether (PPE) and polyetherimide (PEI) were processed by dissolution into epoxy–amine precursors and a subsequent reaction of the precursors. Because the TP concentration was higher than the critical concentration, the phase separation produced a dispersion of crosslinked thermoset (TS) particles into a TP matrix. The morphology of the blends was examined with transmission electron microscopy and dynamic mechanical thermal spectroscopy, which showed completion of the phase separation. The interfacial adhesion at the TP-matrix/TS-particle interface was estimated on TP/TS bilayers to be 10 J/m2 in PEI blends, whereas it was 70 J/m2 in PPE blends, where there is strong evidence for in situ grafting between PPE phenolic chain ends and glycidyl functions of the reactive TS. Yielding in the compressive mode occurred at an intermediate yield stress between the components' values, and the anelastic deformation was separated from the plastic deformation. Fractures in the tensile mode occurred through debonding at the matrix/particle interfaces and coalescence of these defects, which led to microcrack formation and brittle failure. Mode I fracture toughness was, therefore, higher for PPE blends than for PEI blends, a result of the higher interfacial adhesion. However, a decrease from pure TP was observed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 363–373, 2001

Epoxy−Diamine Thermoset/Thermoplastic Blends. 1. Rates of Reactions before and after Phase Separation

Rates of epoxy−amine reactions in thermoset/thermoplastic blends with different thermoplastic concentrations were studied. The selected thermoset system was bisphenol A diglycidyl ether cured with 4,4‘-methylenebis[3-chloro-2,6-diethylaniline] in the presence of various concentrations of polyetherimide (PEI) (10−64 wt %). As the initial systems are homogeneous, the rate constants for the epoxy−amine neat system and the rate constants of the blends are the same, the addition of PEI in the epoxy−amine system leads only to a dilution of reactive groups during this first step. But due to the epoxy−amine reaction, a liquid−liquid phase separation occurs at a given conversion (in the range 0.2−0.4). At the same time and for PEI concentrations equal or higher than 30 wt %, a sudden increase of the reaction rate is observed from experimental results. Comparison between blends based on PEI and polystyrene (PS) shows that after phase separation the reaction rate of the PS blend was higher than the PEI blend due to ...

Asymmetric hollow fiber membranes prepared from miscible polybenzimidazole and polyetherimide blends

We have studied the thermal and mechanical properties, miscibility and morphology, and separation performance of polybenzimidazole (PBI)/polyetherimide (PEI) composite hollow fiber membranes. These composite hollow fibers were wet-spun from dopes containing 25.6 wt% solids in N, N-dimethylacetamide (DMAc) with different PBI/PEI ratios. Water was used as the external coagulant, while either H 2O or DMAc/H 2O mixture was employed as the bore fluid. Thermal mechanical analyzer (TMA) data indicate that these composite hollow fibers are miscible blend membranes. The molecular interaction between PBI and PEI are so strong that their miscibility appears to be independent of bore fluid chemistry, bore fluid flow rate, methanol and hot ethylene glycol treatments. The T g values of wet-spun PBI/PEI blend hollow fiber follow the theoretical prediction of the Fox equation. Both SEM photographs and gas permeation data indicate that an increase in PBI percentage in the spinning solutions resulted in a hollow fiber with a tighter morphology, a lesser layer of finger-like voids and a significantly lower gas permeance. The tensile strength of wet-spun PBI/PEI blend hollow fiber membranes seems to be independent of PBI concentration, while their elongation at break decreases with an increase in PBI concentration.

The role of partial miscibility on the properties of ternary blends of liquid crystalline copolyesters and polyetherimide

Binary blends of liquid crystalline copoly(oxybenzoate-p-ethylene terephthalate) at molar ratio 60/40, POB-PET, and polyetherimide (PEI) were investigated with differential scanning calorimetry and polarised optical microscopy. It was found that POB-PET and PEI were partially miscible when PEI was the major component. Adding a small amount (5 phr) of POB-PET to the originally immiscible blends of liquid crystalline copoly(oxybenzoate-naphthalate) (73/27), Vectra, and PEI resulted in better interfacial adhesions between Vectra and PEI as evidenced by the morphological observations with scanning electron microscopy. The enhancement in the interfacial adhesions caused an increase in the ultimate tensile strength and the impact strength of these ternary blends of Vectra, POB-PET and PEI as compared to that of the corresponding binary blends of Vectra and PEI in an injection molding process.

Prepregs and laminates of polyetherimide-reinforced by a thermotropic LCP

Unidirectional sheets (prepregs) of blends of polyetherimide (PEI) with a liquid crystalline polymer (LCP) are prepared. The mechanical properties of prepregs at directions of 0°, 45°, and 90° to the machine direction are investigated as a function of draw ratio and LCP concentration. The results show that drawing significantly increases the tensile strength and modulus of prepregs in the machine direction and only slightly decreases these properties in the transverse direction. An increase in the LCP content greatly enhances the tensile strength and modulus in the machine direction but decreases these properties in the 45° and 90° directions. The strain at break of prepregs decreases with LCP content in all directions tested. An abrupt drop in the tensile strength, modulus, and strain at break of prepregs occurs in the 45° and 90° directions when LCP content reaches 40%. Prepregs are used to manufacture unidirectional and quasi-isotropic laminates. Unidirectional laminates show mechanical properties close to those of the corresponding prepregs. The tensile modulus of quasi-isotropic laminates exhibits a continuous increase with increasing LCP content while the tensile strength increases with an LCP content up to 30%, then it decreases rapidly. The morphology of LCP in prepregs is observed to change from disperse to continuous at LCP contents of 40 and 50%. This effect is found to be responsible for the large decrease in tensile strength of prepregs in the 45° and 90° directions and quasi-isotropic laminates at higher LCP concentration. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:329–340, 1997

Mechanical properties of polycarbonate–polysulfone and polycarbonate–polyetherimide blends

AbstractFive, ten, and twenty percent by weight blends of polysulfone in polycarbonate and polyetherimide in polycarbonate were produced by melt blending. The materials were injection molded into plaques. Mechanical analysis consisting of tensile, pendulum impact, and ballistic impact testing was conducted using the plaques or samples machined from the plaques. The average impact strength and percentage of ductile failures decreased with increasing composition of polysulfone and polyetherimide. The tensile test results indicate that a relationship exists between the percent composition and the yield strength for the blends with the blends showing an improvement in tensile strength. The ballistic testing results show that a possibly linear relationship exists between the percent composition and the critical velocity for complete penetration. Differential scanning calorimetry was conducted to measure the glass transition temperatures of the materials. The presence of two glass transition temperatures and lack of transparency have indicated that the blends are immiscible. © 1995 John Wiley & Sons, Inc.

Miscibility and fracture behaviour of epoxy resin-nitrated polyetherimide blends

Nitrated polyethermide (NI-PEI) was obtained by chemically modifying a commercially available polyetherimide (PEI) and was characterized by nuclear magnetic resonance and infra-red spectroscopies, elemental analysis and viscometry. NI-PEI and NI-PEI/PEI mixtures were blended with an epoxy resin (MY0510) which was cured with 3,3′-diaminodiphenolsulfone. The morphology and fracture behaviour of these blends were examined by dynamic mechanical thermal analysis and by a three-point bending fracture test. A two-phase morphology exists with substantial toughening occurring at PEI and NI-PEI concentrations of 5 and 10 wt%.

The Tribological Behavior of Blends of Polyetheretherketone (PEEK) and Polyetherimide (PEI) at Elevated Temperatures

The friction and wear under dry sliding conditions of injection molded blends of Polyetheretherketone (PEEK) and Polyetherimide (PEI) at temperatures from 20°C to 232°C were investigated on a pin-on-disk apparatus. The friction and wear results were correlated to results obtained from dynamic mechanical thermal analysis (DMTA) temperature scans performed on each of the materials. It was found that tan δ peaks corresponding to α transitions occurring in the vicinity of the glass transition temperature (Tg) coincided with catastrophic tribological failure in the case of PEI and the amorphous PEEK/PEI blends. PEEK and the annealed 70% PEEK/30% PEI blend, exhibited marked increases in friction and wear at and above the Tg. The absence of catastrophic tribological failure in PEEK and the annealed 70/30 blend in the vicinity of the glass transition temperature corresponded to a transitions of significantly lesser strength (i.e. lower tan δ peak values) than those observed in PEI and the amorphous blends. Betwee...

Mechanical properties of in situ composites based on partially miscible blends of polyetherimide and liquid crystalline polymers

AbstractResults related to the mechanical properties of in situ composites based on partially miscible blends of polyetherimide (Ultem) and liquid crystalline polymers (HX1000 and HX4000) are discussed. It is observed that, at least in terms of the tensile and flexural modulus, there is a positive deviation from the law of mixtures. These results are analyzed and an attempt is made to explain the origin of this synergistic behavior based upon morphological data. The behavior of these partially miscible systems is compared to that of an immiscible system (Ultem/Vectra) and also that of glass‐reinforced Ultem. Using blends subjected to two passes through a single screw extruder, and thereby increasing the mixing history of the Ultem/HX4000 blend, led to improved dispersion but did not lead to any measurable improvement, within experimental error, in the tensile modulus or ultimate strength (though the toughness was enhanced). The dynamic creep compliance was measured and the creep behavior with composition and temperature is discussed. The data seem to suggest that a number of factors (including partial miscibility, the properties of the specific LCP chosen as the reinforcement and the final blend morphology) all interact in a complex and as yet undetermined manner to produce the enhanced mechanical properties.