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Polyaryletherketone is a kind of special engineering plastics with excellent comprehensive properties, high strength, good stability, and almost insoluble in any common solvent except concentrated sulfuric acid at room temperature. However, its high processing temperature also hinders its application and development in the foam. Here, a series of polyetheretherketone (PEEK) and diphenyl polyetheretherketone (PEDEK) composite foams are prepared by temperature induced phase separation, using diphenyl sulfone as solvent. The microstructure, thermal and mechanical properties of PEEK and PEDEK foam are compared. Highly porous PEEK and PEDEK foams with densities ranging from 0.13 to 0.25 g cm−3, with compressive strength ranging from 0.68 to 2.6 MPa, respectively, are produced. Meanwhile, the introduction of diphenyl structure can effectively improve the performance of PEEK foams at high temperature. It is found that PEDEK foam has a higher operating temperature than PEEK, and the compressive strength of 0.24 g cm−3 foam is still ≈1 MPa at 200 °C. [ABSTRACT FROM AUTHOR]

Both morphological structure and chemical composition are the important factors that determine the electromagnetic wave (EMW) absorption properties of EMW absorbers. Herein, hierarchical porous carbon (HPPC) was synthesized by using polyetheretherketone (PEEK) as the starting material via the salt template method combined with KOH activation. Then, taking advantage of the hierarchical porous characteristics of the carbon, a novel EMW absorber (HPPC/CoNi) was synthesized by in situ growth of CoNi bimetallic alloys inside the above porous carbon. The as-synthesized HPPC/CoNi exhibits excellent EMW absorption performance with a minimum reflection loss (RLmin) value of −65.56 dB at 2.00 mm and a maximum effective absorption bandwidth (EAB) of 5.92 GHz at 1.80 mm. The superior EMW absorption property is ascribable to the multiple reflection/scattering induced by the hierarchical porous structure of HPPC, dielectric loss, magnetic loss, and good impedance matching. The results show that HPPC/CoNi is a potential EMW absorber with characteristics of ultra-light weight, ultrathin thickness, broad bandwidth, and strong absorption. [ABSTRACT FROM AUTHOR]

The preparation of the electromagnetic wave (EMW) absorbing materials with 3D porous structural, light weight, and high mechanical strength has been receiving greater attention for a long time. A series of light‐weight polyetheretherketone/graphite/FeCo ternary heterogeneous composite foams (PEEK/C/FeCo) with high mechanical strength are prepared via thermally induced phase separation. Based on the high compressive strength of PEEK resin and its stable skeleton formed by thermally induced phase separation, the composite foam has high compressive strength and low density. In addition, during the thermally induced phase separation process, porous structures are formed inside the PEEK, and graphite and FeCo particles are uniformly dispersed between the pore structures, the composite foams possess excellent porous structure, moderate dielectric loss, and magnetic loss, exhibiting good absorbing properties. With the low density of 0.49 g cm−3 and high compressive strength of 6.40 MPa, the as‐synthesized optimal sample (PEEK‐50/C‐40/FeCo‐10) achieves a minimum reflection loss up to −35.9 dB covering a bandwidth of 3.6 GHz for a thickness of 1.5 mm. In a word, this study provides a novel, economical, and efficient way to obtain a light foam with high mechanical strength and good EMW absorbing property. [ABSTRACT FROM AUTHOR]

The wollastonite was grafted with different silane coupling agents, which could improve interface adhesion. Wollastonite and modified wollastonite-reinforced poly(ether ether ketone) (PEEK) composites were prepared by melt blending. The mechanical properties, rheology behavior, and thermal properties of the composites were investigated. The modified wollastonite-reinforced PEEK composites exhibited better mechanical properties than the unmodified wollastonite-reinforced PEEK composites based on good interfacial adhesion. The composites had lower activation volume and complex shear viscosity. Furthermore, the modified wollastonite-reinforced PEEK composites had higher crystallization peak temperature ([T.sub.c]) and crystalline fraction ([χ.sub.c]) compared with the unmodified wollastonite-reinforced PEEK composites. This study shows that the traditional silane coupling agents could effectively improve the performance of PEEK composites. POLYM. ENG. SCI., 51:1051-1058, 2011. [C]2011 Society of Plastics Engineers, INTRODUCTION Poly(ether ether ketone) (PEEK) is a kind of semicrystalline thermoplastic polymer with outstanding performance such as high temperature resistance, excellent chemical resistance, and superior mechanical properties [1, 2]. To [...]

As an important part of electronic packaging materials, low‐dielectric materials can ensure effective signal transmission between electronic components and have an impact on the performance of microprocessor chips. Herein, a porous poly(ether sulfone) membrane with low dielectric constant is fabricated via a breath figure method to meet requirements for high performance of new packaging materials. Perfluorononyl oxide side groups are introduced into the molecular structure of a block poly(ether sulfone) polymer by post‐grafting, and the pore‐making process and the dielectric properties of the materials are studied. The resulting multi‐block copolymers are found to have different electric and thermal properties depending on the molar ratio of perfluorononyl oxide side groups. Regular honeycomb pores can be formed with a polymer segment length of 8/16. Besides, the porous membranes with ordered pore structure on the surface possess low dielectric constant values ranging from 1.57 to 2.19 at 10 kHz. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

An egg white-derived carbon/magnetic nanoparticles/water-soluble graphene oxide composite absorber (EWC/MNPs/WSGO) was specially designed and synthesized via a facile sol–gel process with subsequent high-temperature pyrolysis. Magnetic nanoparticles (MNPs) were used to bring magnetic loss ability and improve the electromagnetic matching condition. Water-soluble graphene oxide (WSGO) was also used to adjust the absorption properties of the composite absorber. Moreover, egg white, which is liquid biomass, enables uniform dispersion of MNPs and WSGO within the absorber, allowing full use of the synergistic effect of each component. Benefiting from the excellent homogeneous structure, moderate dielectric loss and magnetic loss, strongly matched impedance, and multiple polarization are achieved. The as-synthesized optimal sample (EWC/MNPs/WSGO-1.0) exhibits superior electromagnetic wave absorption properties. The minimum reflection loss (RLmin) reaches −51.5 dB, and the effective absorption bandwidth (EAB, RL < −10 dB) is 3.4 GHz at a thickness of 1.6 mm. Compared with the reported bio-derived carbonaceous composite absorbers, EWC/MNPs/WSGO has great potential to be a lightweight and efficient electromagnetic wave absorption material in the frequency range of 2 to 18 GHz. [ABSTRACT FROM AUTHOR]

With the rapid development of electronic devices and wireless communication tools, it is urgent to design and fabricate low-cost, lightweight and effective electromagnetic absorption materials to solve interference of electromagnetic waves. Herein, a new strategy toward porous carbon/graphite nanosheet/ferromagnetic nanoparticle (PC/GNS/Fe) composites was designed to investigate the influence of crystalline carbon on electromagnetic wave absorption. To begin with, graphite nanosheets (GNSs) were incorporated into the porous polyimide by in situ polymerization, and Fe were added as a magnetic particle source and an agent to regulate the pore size. A series of PC/GNS/Fe composite absorbents were obtained. The direct carbonization of porous polymer precursors was beneficial to the design of the pore structure of materials. A hierarchically porous structure derived from the phase separation process was well maintained in the polyimide pyrolysis process. The results demonstrated that the presence of crystalline carbon could influence the reflection loss value and the frequency range. Hence, the absorbing performance can be optimized by adjusting the pore structure and the content of crystalline carbon in materials, which is conducive to obtaining electromagnetic wave absorption materials with excellent comprehensive performance. [ABSTRACT FROM AUTHOR]

The conventional poly(ether ether ketone) (PEEK) and two other PEEK copolymers (PEEEKK-PEK and PEEEKK-PEEEK) were successfully synthesized and investigated on their thermal stabilities, mechanical properties, and rheological behaviors. Both of the PEEEKK-PEK and PEEEKK-PEEEK were composed of the same chemical components with conventional PEEK (phenyl–ether–ketone equals 3:2:1), but the sequences of their components (phenyl, ether, and ketone) were different. Differential scanning calorimetry analysis and dynamic mechanical analysis indicate that PEEEKK-PEK and PEEEKK-PEEEK have extremely close glass transition temperatures and melting points with conventional PEEK, which suggests their similar operating temperatures. They also process similarly high mechanical properties based on their stress–strain tests. However, PEEEKK-PEK, PEEEKK-PEEEK, and PEEK exhibit significant differences in their rheological behaviors; PEEEKK-PEK even shows an excessively low melt viscosity (51% of PEEK). These results reveal the effects of sequence distribution on polymer properties and thereby demonstrate the processing viscosity of PEEK could be decreased without sacrificing its operating temperature or material performances. [ABSTRACT FROM AUTHOR]

A pre-modification method and a post-modification method have been developed to fabricate rice husk-based porous carbon and magnetic particles composite absorbers (RHPC/Fe and RHPC/Co). Magnetic Fe and Co particles were selected to incorporate into rice husk-based porous carbon to make full use of the synergistic effect between dielectric loss and magnetic loss. The structure, morphology, magnetic properties and electromagnetic (EM) wave absorption performance of the synthesized absorbers were investigated in detail. Inside the porous structure, the incident EM wave can be attenuated by means of Debye dipolar relaxation-derived dielectric loss and exchange resonance-derived magnetic loss through multiple scattering and absorption. For RHPC/Fe, at a thickness of 1.4 mm, a reflection loss (RL) value of −21.8 dB was achieved with the effective absorption bandwidth (RL ≤−10 dB) of 5.6 GHz. For RHPC/Co, an RL value of −40.1 dB was obtained with the effective absorption bandwidth (RL ≤−10 dB) of 2.7 GHz at a thickness of 1.8 mm. The excellent EM wave dissipation ability of RHPC/Fe and RHPC/Co can be attributed to the good EM impedance matching condition, quarter-wavelength cancellation and strong EM wave attenuation inside the absorber. Consequently, considering the EM wave absorption performance, the RHPC/Fe and RHPC/Co synthesized in this work are promising candidates in the field of EM wave attenuation. [ABSTRACT FROM AUTHOR]

A series of high-performance polyethersulfone, which had pendent carbazole moieties (Cz-PES 1–3), have been designed and successfully synthesized for an application in a write-once read-many type memory device as the active polymer layer. The memory performance can be tuned by changing the substituent in the Cz derivatives units. Cz-PES 3 with excellent thermal properties (Tg = 185°C and Td = 378°C) exhibits the best memory performance. For Cz-PES 3-based device indium tin oxide/Cz-PES 3/aluminum, the turn-on voltage is 2.5 V and the ON/OFF current ratio is higher than 106. Moreover, the data can be maintained for longer than 3 × 105 s once written and can be read for more than 450 cycles under a reading voltage of 1.0 V at ambient conditions. Thus Cz-PES 3 can serve as an excellent memory material in the data storage field of next generation. [ABSTRACT FROM AUTHOR]

ABSTRACT A high-performance polymer polyethersulfone (CN-Azo-PES), with a flexible ethoxyl linkage between the azobenzene chromophore side chain and the PES backbone, has been designed and successfully synthesized for an application in a WORM type memory device as an active polymer layer. CN-Azo-PES has excellent thermal properties with Tg of 151°C and the degradation temperature higher than 373°C, which can contribute to a better performance of the device. The device based on CN-Azo-PES exhibits a write-once read-many (WORM) type memory performance with an onset voltage as low as −1.0 V and an ON/OFF current ratio higher than 102 at a reading voltage of 0.4 V. Moreover, the data can be maintained for longer than 4 × 105 s once written and can be read for more than 400 cycles under a reading voltage of 0.4 V. Thus CN-Azo-PES can serve as an energy saving memory material in the data storage field of next generation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42644. [ABSTRACT FROM AUTHOR]

The rheological, mechanical, and thermal properties of random, alternating, and three block of polyether sulfone/polyetherethersulfone copolymers are compared. These copolymers have similar molecular weights and chemical composition (phenyl:ether:sulfone = 7:4:3). Differential scanning calorimetry and dynamic mechanical analysis results indicate that all copolymers possess extremely close glass transition temperature. On this basis, it is interesting to find that the alternating copolymer exhibits the melt viscosity of 281 Pa·s, which is much lower than those of random copolymer (1641 Pa·s). For block copolymers, the gradual increase with the preceding length increases in melt viscosity. In addition, the stress–strain test curves of copolymers were investigated, which revealed that sequence distribution has important influence on the tensile strengths and elongations at break. All these can be highly related to their different sequence distribution. These results obtained were discussed and interpreted. [ABSTRACT FROM PUBLISHER]

Random, block, and alternative polyethersulfone/polyetherethersulfone copolymers (phenyl: ether: sulfone =7 : 4 : 3) with similar molecular weights and polydispersity were synthesized using different synthetic strategies. DSC and DMA analyses indicated that all copolymers are amorphous and possess extremely close glass transition temperature. The random copolymer displayed higher modulus and complex viscosity. It is interesting to find that the alternative copolymer exhibited a melt viscosity of 281 Pa s, which is much lower than that of the block copolymer (646 Pa s) and the random copolymer (1641 Pa s) at 4 s−1. Moreover, the alternative copolymer showed obviously higher elongation at break of 101.9%. These behaviors were highly related to their different sequence distribution. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40149. [ABSTRACT FROM AUTHOR]

A novel transparent Co0.2Fe2.8O4@SiO2–polyetheretherketone hybrid material is prepared for electromagnetic interference shielding via in situ sol–gel process. 20% amino-functionalized polyetheretherketone (AFPEEK), containing trifluoromethyl units with excellent solubility is designed and synthesized to improve the stability and mechanical properties of Co0.2Fe2.8O4@SiO2 nanoparticles. The hydrophilic nanoparticles and hydrophobic polymer matrix are covalently connected after the effective interface modification with 3-isocyanatopropyltriethoxysilane. SEM and TEM images demonstrate that the strong interaction between inorganic–organic phases results in great improvement of dispersion and compatibility at even 40 wt% nanoparticles contents. The functional integration of organic polymer and inorganic nanoparticles leads to excellent comprehensive performances such as high transparency, thermal stability and mechanical properties of the hybrid material, as well as the high adhesion with substrate, which benefits its application as coating materials. This high performance material exhibits good superparamagnetic behaviour and microwave electromagnetic properties (RLmax∼−13 dB), which can be utilized as a promising electromagnetic interference shielding material. [ABSTRACT FROM AUTHOR]

This study reported a method to prepare fully aromatic macrocycle-terminated polyimides (MC-PI). The macrocycle of aryl ether ketones was prepared from (4-amino)phenylhydroquinone and a di-fluoro monomer under pseudo high dilution condition. Novel aromatic fully MC-PI oligomers were successfully prepared by the reaction of 2,3,3′,4′-biphenyltetracarboxylic diandhydride with 2,5-bis(4′-aminophenoxy)-biphenyl and sulfur-containing macrocycle of aryl ether ketone. The MC-PI oligomers were cross-linkable in the heating, and the glass transition temperatures of the polyimides increased after thermally cured. The cross-linking reaction of MC-PI could form fully aromatic thermosetting polyimide by ring-opening reaction. After cross-linking, these polyimides showed higher glass transition temperatures and excellent thermal stability. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Two types of antioxidants (a phenolic antioxidant and a phosphorous antioxidant) were used to improve the stability of poly (ether ether ketone) (PEEK). To evaluate the effect of the antioxidants on the properties of PEEK and the stabilization mechanism, some characterization methods were carried out, such as rheometer, TGA, and electron spin resonance (ESR). The results indicated that the efficiency of the phosphorous antioxidant (DS) in improving the stability of PEEK was better than that of the phenolic antioxidant (DN) and the thermal stability of PEEK sample containing 0.07 wt% DS was the best among all samples due to the decrease of the free radicals density, as proven by ESR measurement. The possible stabilization mechanism of the antioxidants to PEEK was proposed to reveal the reason that caused the different performances of the two types of antioxidants to PEEK. [ABSTRACT FROM PUBLISHER]

A novel fully aromatic sul-containing macrocycle-terminated poly(aryl ether ketone) (PAEK-C) was prepared by condensation of macrocyclic aryl ether ketone dimers containing hydroxyphenyl groups and a fluorine end-capped poly(aryl ether ketone) oligomer. The PAEK-C exhibited high thermal stability due to its wholly aromatic structure. The crosslinking reaction of PAEK-C could allow fully aromatic thermoset poly(aryl ether ketone) by ring-opening reaction without the existence of catalyst. After crosslinking, the glass transition temperature of the thermoset increased greatly. The obtained poly(aryl ether ketone) thermoset had good thermal stability with 5% weight loss temperature above 500oC in N2. [ABSTRACT FROM AUTHOR]

Different structure silane-terminated polymer oligomers were synthesized and grafted onto the surface of wollastonite particles. The prepared grafted-wollastonite particles (g-W) were then incorporated into poly (ether ether ketone) (PEEK) matrix via melting blend. The properties of the PEEK composites were investigated using differential scanning calorimetry, universal tester and rheometer. The results showed that the mechanical properties of the PEEK/g-W composites were markedly enhanced, the complex viscosity of PEEK/g-W composites was increased, and both the peak crystallization temperature (Tc) and crystalline fraction (χc) of the g-W-reinforced PEEK composites were significantly higher in comparison with those of non-treated wollastonite-reinforced PEEK composites. It is concluded that these results were due to the strong interaction between the grafted-wollastonite particles and the PEEK matrix, and the properties of the PEEK/g-W composites were slightly different because of the different structure of the polymer oligomers. [ABSTRACT FROM AUTHOR]

This study reports a method to prepare fully aromatic poly(ether ketone) thermosets. The cyclization of 2′,5′‐dimethoxy[1,1′‐biphenyl]‐2,5‐diol and a difluoro monomer was carried out under pseudo high dilution condition. Two types of fully aromatic poly(ether ketone)s with macrocycle were successfully prepared by copolymerization of macrocycle of aryl ether ketone containing hydroxyphenyl groups, 4,4′‐(hexafluoroisopropylidene)diphenol (HFBPA), and 4,4‐difluorobenzophenone. The obtained copolymers have high molecular mass, good solubility, and high glass transition temperatures in the presence of CsF, the crosslinking reaction of copolymers occurred and afforded fully aromatic thermoset poly(aryl ether ketone)s by ring‐opening reaction driven by entropy. After crosslinking, these copolymers show much higher glass transition temperatures, excellent thermal stability, and better mechanical strength. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7002–7010, 2008 [ABSTRACT FROM AUTHOR]

A new monomer, (2,5-dimethoxy)phenylhydroquinone (DMPH), was prepared in a two-step synthetic procedure. One aromatic poly(ether ether ketone)s with 2,5-dimethoxy phenyl side group (DMP-PEEK) was synthesized via an aromatic nucleophilic substitution reaction with 4,4'-difluorobenzophenone (DFB). Poly(ether ether ketone)s with 2,5-dihydroxy phenyl side group (DHP-PEEK) was obtained via hydrolysis of methoxy group on the DMP-PEEK. Both of the high molecular weight polymers could be obtained despite the steric effect of the bulky pendant groups. The two polymers have good solubility at room temperature. [ABSTRACT FROM AUTHOR]

Nowadays, demands for the utilization of thin membranes in the next generation of direct methanol fuel cells become urgent to acquire the high power density. However, the fuel crossover coefficient is inversely proportional to the thickness of membranes which easily causes the reduction of the energy density. Hence, we propose a thin reinforced pore-filling composite membrane that is fabricated from a highly sulfonated poly (ether ether ketone) electrolyte and a high mechanical strength semi-crystalline poly (ether ether ketone) porous matrix. The semi-crystalline poly (ether ether ketone) derived from a soluble precursor of PEEK-1,3-dioxolane is first reported to be used for preparing the porous membrane. Uniform pore structures of the porous matrix are obtained by a water induced phase inversion method. As-prepared porous PEEK shows high toughness with an elongation at break of 8.2%. The reinforced composite membrane (only 20 μm) demonstrates superior methanol tolerance (3.2 × 10−7 cm2 s−1) and good proton conductivity due to the packed-acid structure. In addition, the membrane electrode assembly indicates a preferable behavior in single cell performance, with an open circuit voltage of 0.53 V and a peak power density of 34.6 mW/cm2. Image 1 • Thin reinforced pore-filling PEM based on semi-crystalline PEEK. • Reversible chemical modification of soluble PEEK. • Pore fabrication via water induced phase inversion method. • Significant membrane resistance to methanol crossover and swelling. • Superior single cell performance in 10 M methanol. [ABSTRACT FROM AUTHOR]