Crystallinity of poly(arylene ether nitrile) copolymers containing hydroquinone and bisphenol A segments

The hydroquinone (HQ) and bisphenol A (BPA) type poly(arylene ether nitrile) (PEN) (HQ/BPA‐PEN) were synthesized through nucleophilic aromatic substitution polymerization from HQ, BPA, and 2,6‐dichlorobenzonitrile (DCBN). The prepared copolymers were characterized by intrinsic viscosity, Fourier transform infrared (FTIR), and dynamic rheological analysis. The properties of resultant copolymers were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and mechanical testing. The results showed that the PEN copolymers exhibited crystallization performance with excellent thermal and mechanical properties. HQ/BPA‐PEN10 was made into films by solution‐casting process and then were treated at different temperatures (200, 260, 280, 300, 310, and 320 °C) for different times (1, 2, 3, 4, and 5 h) to investigate the crystallinity. Results showed that when isothermal treatment temperature is 310 °C and isothermal treating time is 4 h, HQ/BPA‐PEN10 showed best properties. At this condition, the melting enthalpy, crystallinity, tensile strength, and elongation at break of the sample is 17.7 J/g, 14.11%, 132.9 MPa, and 6.1%, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46412.     

Design and properties of polyarylene ether nitrile copolymers with improved elongation at break

Polyarylene ether nitrile (PEN) based on biphenol exhibits a high glass transition temperature of 216°C, a high tensile strength of 110 MPa, and low elongation at break of approximately 4%. A series of PEN random copolymers with improved elongation at break were synthesized using various bisphenol compounds and 2,6-dichlorobenzonitrile (DCBN). The resulting PEN random copolymers exhibited a high glass transition temperature and thermal stability up to 513°C in a nitrogen atmosphere. PEN copolymers were amorphous and could easily be cast into transparent films with a tensile strength of 97.93–117.88 MPa and tensile modulus of 2187.98–2558.44 MPa. Most importantly, elongation at break of these PEN copolymers was higher than 13%. PEN copolymer films had a dielectric constant of 3.77–3.89 at 1 kHz and extremely low dielectric loss (<0.02). At the same time, the breakdown strength of PEN was in the range of 137.92–198.19 kV/mm and energy storage density was in the range of 0.32–0.68 J/cm³. Excellent mechanical, thermal, and dielectric properties of PEN make it possible to use them as high-temperature resistant dielectrics to act on high-temperature resistant insulated cables.     

Synthesis and properties of crosslinked poly(arylene ether nitriles) containing pendant phthalonitrile

In this study, poly(arylene ether nitriles) containing pendant carboxyl groups (PEN‐COOH) was first synthesized via nucleophilic aromatic substitution reaction from phenolphthalein, hydroquinone and 2,6‐dicholorobenzonitrile. Then, poly(arylene ether nitriles) with pendant phthalonitrile groups (PEN‐CN) was obtained via the Yamazaki–Higashi phosphorylation route from 4‐(4‐aminophenoxy)phthalonitrile (APN) with PEN‐COOH in the presence of CaCl₂, thus the phthalonitrile as pendant groups in PEN‐CN were easily crosslinked by further thermal treatment. The effect of crosslinking density on the thermal stabilities, dielectric properties and water absorption of the PEN‐CNs was investigated. These results showed that the T_g of PEN‐CN was improved from 182 to 213°C, dielectric constant (ε) was increased from 3.1 to 3.9, and dielectric loss (tan δ) was decreased from 0.090 to 0.013 at 1 kHz. The water absorption of PEN‐CNs after thermal crosslinking was <1.01 wt %, which showed excellent water resisting property. Therefore, this kind of poly(arylene ether nitriles) containing pendant phthalonitrile could be a good candidate as matrix resins for high‐performance polymeric materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of nitrile functionalized graphene on the properties of poly(arylene ether nitrile) nanocomposites

In this study, novel nitrile functionalized graphene (GN‐nitrile)/poly(arylene ether nitrile) (PEN) nanocomposites were prepared by an easy solution‐casting method and investigated for the effect of surface modification on the dielectric, mechanical and thermal properties. Graphene (GN) was first functionalized by introduction of nitrile groups onto the GN plane, which was confirmed by scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, thermogravimetric analysis and dispersibility research. Compared with pure GN, the grafted nitrile groups on the GN‐nitrile can interact with nitrile groups in PEN and lead to flat but better dispersion and stronger adhesion in/to the PEN matrix. Consequently, GN‐nitrile had a more significant enhancement effect on the properties of PEN. The dielectric constant of the PEN/GN‐nitrile nanocomposite with 5 wt% GN‐nitrile reaches 11.5 at 100 Hz, which is much larger than that of the pure PEN matrix (3.1). Meanwhile, dielectric loss is quite small and stable and the dielectric properties showed little frequency dependence. For 5 wt% GN‐nitrile reinforced PEN composites, increases of 17.6% in tensile strength, 26.4% in tensile modulus and 21 °C in T_d5% were obtained. All PEN/GN‐nitrile nanocomposite films can stand high temperature, up to 480 °C. Hence, novel dielectric PEN/GN‐nitrile nanocomposite films with excellent mechanical and thermal properties can be used as dielectric materials under some critical circumstances such as high wear and temperature. Copyright © 2012 Society of Chemical Industry     

Compatibility,rheological, and thermal properties of the melt blends of PEN (HQ/PP) with PEN (HQ/RS)

Two kinds of polyarylene ether nitriles (PEN) copolymers PEN (HQ/PP) and PEN (HQ/RS) were synthesized using 2,6-dicholorobenzonitrile (DCBN) with equal molar of phenolphthalein (PP) and hydroquinone (HQ), DCBN with equal molar of HQ and resorcin (RS), respectively. The melt-mixed blends of two PENs over the complete composition range were characterized by dynamic mechanical analyses (DMA), tensile testing, scanning electronic microscopy (SEM), and capillary rheometer test for their compatibility, thermal, mechanical, and melt flow properties study. DMA show a considerable compatibility between the two PENs. Morphology examinations reveal good component dispersion and strong interface adhesion. The capillary rheometer test found that the blending of PEN (HQ/RS) enhanced the fluidity of the PEN (HQ/PP)/PEN (HQ/RS) blends by reducing its viscosity, which is beneficial to the processability of PEN (HQ/PP). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚芳醚腈合金的制备及性能研究

将2类聚芳醚腈（PEN）共聚物PEN（HQ／RS）和PEN（HQ／PP）,按不同质量比通过熔融共混制备PEN合金材料,测试其相容性、力学性能和热性能,发现聚合物合金在PEN（HQ／RS）质量分数分别为20％和80％时相容性良好,PEN（HQ／RS）的加入改善了PEN（HQ／PP）的加工性能,实验中不同质量比的合金均具有优良的力学性能和热性能。     

Effect of curing behaviors on the properties of poly(arylene ether nitrile) end-capped with phthalonitrile

Poly(arylene ether nitrile) (PEN) end-capped with phthalonitrile (PEN-n) was synthesized by incorporating phthalonitrile into the terminals of PEN. The as-prepared flexible PEN-n (after elevated temperature treatment) was characterized by infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, and rheological measurements. In addition, the effects of curing behaviors on properties of PEN-n films were studied by thermal, dielectric and mechanical measurements. Differential scanning calorimetry analysis showed that glass transition temperature of PEN-n was improved from 176 to 232°C as the curing temperature and time increased. Thermal gravimetric analysis revealed that initial decomposition temperature of PEN-n cured at 320°C for 2 h was 570°C. Mechanical properties showed that tensile strength of PEN-n uncured and cured at 320°C for 3 h was 85 and 97 MPa, respectively. The dielectric properties showed that the dielectric constant of PEN-n film decreased from 4.0 to 3.1 as the curing time increased and dielectric loss of PEN-n was 0.01 at 100 kHz. This kind of PEN-n film may be used as a good candidate for high-performance polymeric materials. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of surface functionalization on the properties (rheological,mechanical, and dielectric) and microtopography of PEN/CPEN‐f‐CNTs nanocomposites

Novel carboxylic poly(arylene ether nitrile)s (CPEN) functionalized carbon nanotubes (CPEN‐f‐CNTs) were successfully prepared by a simple and effective solvent–thermal route. The CPEN‐f‐CNTs were subsequently used as the novel filler for preparation of high performance poly(arylene ether nitrile)s (PEN) nanocomposites. The SEM characterization of the PEN nanocomposites revealed that the CPEN‐f‐CNTs present better dispersion and interfacial compatibility in the PEN matrix, which was confirmed by the linear rheological analysis (Cole–Cole plots) as well. Consequently, the improved thermal stability (increased initial and maximum decomposition temperature) and enhanced mechanical properties (tensile strength and modulus) were obtained from nanocomposites using CPEN‐f‐CNTs. More importantly, the PEN/CPEN‐f‐CNTs nanocomposites not only show a high dielectric constant but also have low dielectric loss. For example, a dielectric constant of 39.7 and a dielectric loss of 0.076 were observed in the PEN composite with 5 wt% CPEN‐f‐CNTs loading at 100 Hz. Therefore, the flexible PEN/CPEN‐f‐CNTs nanocomposites with outstanding mechanical, thermal and dielectric properties will find wide application in the high energy density capacitors. POLYM. COMPOS., 37:2622–2631, 2016. © 2015 Society of Plastics Engineers     

Effect of nonsolvent on the structures and properties of poly(arylene ether nitrile) films prepared by the phase inversion method

In this study, a series of nonsolvents including ethyl acetate (EAC), acetic acid (HAC), n-butyl alcohol (NBA), iso-propyl alcohol (IPA) and ethanol (EA) were selected during the phase inversion process of poly(arylene ether nitrile) (PEN) films. The mechanism of film formation was tightly related with the interactions among polymer, solvent and nonsolvent. In the case of EAC, the aggregated sphere in P-EAC confirmed the in situ aggregate mechanism of polymer chains during the phase inversion process. As the nonsolvent-polymer interaction increases from HAC, NBA, IPA to EA, the phase inversion mechanism was gradually changed from the delayed to transient, as verified by the morphology transformation from spongy-like to finger-like. Dielectric, mechanical properties of these PEN films are tightly related with the morphological features, while their thermal properties are similar. Among them, P-EAC show the optimal properties for potential application in the low-k films, with a dielectric constant, T_d5%, tensile strength of 1.99, 515.84°C, and 36.08 MPa, respectively. This work can provide references for tailoring the structures and properties of PEN films through rational selection of nonsolvent via the phase inversion method.     

Crystallized polyarylene ether nitrile blends with improved thermal,mechanical, dielectric properties,and processability

In this work, the biphenol polyarylether nitrile (BP‐PEN) films with improved processability were prepared by blending low molecular weight (LMW) with high molecular weight (HMW) of BP‐PEN. The hybrid membrane exhibited excellent thermal stability and mechanical strength. The T_id values of the films were as high as 505°C–522°C. Melting behavior studies indicated that the crystallinity of LMW BP‐PEN was higher than that of HMW, which was confirmed by the X‐ray diffraction (XRD) patterns analysis as well. Scanning electron microscope (SEM) provided additional information on morphology and phase adhesion. Additionally, the polymer crystallinity dependent on dielectric properties of blends films is reported. Most importantly, it is found that the combination of LMW and HMW BP‐PEN would be an effective method to simultaneously increase the mechanical, thermal, dielectric properties, and polymer processability. POLYM. COMPOS., 38:126–131, 2017. © 2015 Society of Plastics Engineers     

Synergetic effect of cyanogen functionalized carbon nanotube and graphene on the mechanical and thermal properties of poly (arylene ether nitrile)

Cyanogen functionalized carbon nanotube and graphene/poly (arylene ether nitrile) (CNT-CN/GN-CN/PEN) nanocomposite films were prepared by a facile solution casting method. The weight ratio of CNT-CN/GN-CN was varied from CNT-dominated to GN-dominated for the purpose of investigating their synergetic effects on the mechanical and thermal properties of PEN nanocomposites. Consequently, GN-CN/PEN composites demonstrated better mechanical and thermal properties than CNT-CN/PEN composites due to larger contact area between GN-CN and PEN matrix. Nevertheless, all CNT-CN/GN-CN/PEN composites exhibit enhanced mechanical properties than those of GN-only nanocomposites. With the increasing of CNT-CN/GN-CN weight ratio, the mechanical properties of CNT-CN/GN-CN/PEN composites increase, then decrease, and reach their maximums when CNT-CN/GN-CN weight ratio is around 4/4. From scanning electron microscope images, it is found that around that point GN-CN is flatly dispersed and CNT-CN is penetrated into GN-CN, capable of transferring stress load and thus decreasing interface loss. Thermal properties of CNT-CN/GN-CN/PEN composites once again confirmed the joint effect of CNT-CN and GN-CN, leading to improved thermal properties. In short, a synergistic effect between one-dimensional (1-D) CNT and two-dimensional (2-D) GN on the mechanical and thermal properties of nanocomposites have been demonstrated in these systems.     

Effects of graphene nanosheets on the dielectric,mechanical, thermal properties,and rheological behaviors of poly(arylene ether nitriles)

Poly(arylene ether nitriles) (PEN) containing various contents of graphene nanosheets (GNs) was prepared via solution‐casting method and investigated for their dielectric, mechanical, thermal, and rheological properties. For PEN/GNs nanocomposite with 5 wt % GNs, the dielectric constant was increased to 9.0 compared with that of neat PEN (3.1) and dielectric losses of all nanocomposites were in the range of 0.019–0.023 at 1 kHz. The tensile modulus and strength were increased about 6 and 14% with 0.5% GNs, respectively. The fracture surfaces of the all PEN/GNs nanocomposites revealed that GNs had good adhesion to PEN matrix. The thermal properties of the nanocomposites showed significant increase with increasing GN loading. For 5 wt % GNs‐reinforced PEN nanocomposite, the temperatures corresponding to a weight loss of 5 wt % (T_d5%) and 30 wt % (T_d30%) increased by about 20 and 13°C, respectively. Rheological properties of the PEN nanocomposites showed a sudden change with the GN fraction and the percolation threshold was about 1 wt % of GNs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synergistic enhancement of mechanical,crystalline and dielectric properties of polyarylene ether nitrile‐based nanocomposites by unidirectional hot stretching–quenching

Copper tetra‐amine phthalocyanine (NH₂‐CuPc) was grafted onto barium titanate (BaTiO₃) whose surface was modified by carboxylic polyarylene ether nitrile (CPEN) to afford a nano‐filler (CPEN‐f‐BaTiO₃@NH₂‐CuPc). Through a solution‐casting method combined with ultrasonic dispersion technology, the obtained CPEN‐f‐BaTiO₃@NH₂‐CuPc was successfully incorporated into biphenyl polyarylene ether nitrile (BP‐PEN) matrix to prepare nanocomposite films with various mass fractions of CPEN‐f‐BaTiO₃@NH₂‐CuPc (0, 2.0, 5.0, 10.0 and 20.0 wt%). After that, the nanocomposite films were unidirectionally stretched with various stretching ratios at 280 °C. All the nanocomposite films show excellent mechanical and thermal stability, which is provided by the BP‐PEN matrix. The crystallinity and mechanical, thermal and dielectric properties of the nanocomposite films are efficiently enhanced after the unidirectional hot‐stretching process. The results show that hot‐stretching is a useful method for improving the mechanical and crystallization behaviors as well as the thermal and dielectric properties of the nanocomposite films. © 2017 Society of Chemical Industry     

Synthesis and crosslinking behavior of a soluble,crosslinkable, and high young modulus poly(arylene ether nitriles) with pendant phthalonitriles

Poly(arylene ether nitriles) (PEN) with pendant phthalonitrile groups (PEN? CN) were obtained via the Yamazaki‐Higashi phosphorylation route of 4‐(4‐aminophenoxy)phthalonitrile (APN) with acid‐contained PEN (PEN? COOH) in the presence of CaCl₂. The chemical structure and molecular weight of PEN? CN were characterized by ¹H‐NMR, Fourier transform infrared spectroscopy, and Gel permeation chromatography. The synthesized PEN? CN had superior solubility in polar organic solvent and can be easily processed into thin films from the solutions of N‐methylpyrrolidone, dimethylsulfoxide, N,N′‐dimethylformamide, dimethylacetamide, and tetrahydrofuran. Compared with PEN? COOH, PEN? CN showed higher thermal stability with 5% weight loss temperatures (T_5%) up to 430°C. The glass transition temperature of PEN? CN was improved from 211 to 235°C measured by differential scanning calorimetry (DSC). In addition, it also exhibited excellent mechanical properties that Young's modulus reached to 3.5 GPa. Meanwhile, the effects of different aromatic amines and Lewis acid on the crosslinking behavior of PEN? CN were investigated by DSC. The results indicated that anhydrous Zinc chloride (ZnCl₂) was the best catalyst to lower the curing temperature among 2,6‐bis(4‐diaminobenzoxy) benzonitrile, 4,4‐diaminediphenyl sulfone, APN and ZnCl₂. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of multiblock semi-crystalline hydrophobic poly(ether ether ketone)–hydrophilic disulfonated poly(arylene ether sulfone) copolymers for proton exchange membranes

Multiblock copolymers based on alternating segments of telechelic phenoxide terminated hydrophilic fully disulfonated poly(arylene ether sulfone) (BPS100) and decafluorobiphenyl (DFBP) terminated hydrophobic poly(arylene ether ketimine) (PEEKt), were synthesized from the hydrophilic and ketimine-protected amorphous hydrophobic telechelic oligomers by nucleophilic coupling reactions. After film formation from DMSO, the copolymer was acidified, which converted the ketimine to semi-crystalline ketone segments and the sulfonate salts to disulfonic acids. A semi-crystalline phase with a T_m of 325 °C was confirmed. The semi-crystalline multiblock copolymer membranes were tough, ductile and solvent resistant. Fundamental properties as proton exchange membranes (PEMs) showed enhanced conductivities under fully hydrated and reduced humidity conditions. These multiblock copolymers exhibited low in-plane anisotropic swelling behavior, in contrast to the random copolymers.     

Synthesis of poly(arylene ether nitrile ketone)s bearing phthalazinone moiety and their properties

Copoly(arylene ether nitrile ketone)s bearing phthalazinone moiety (PPENKs) were successfully synthesized by the nucleophilic substitution reaction of 4-(4-hydroxylphenyl)-2,3-phthalazin-1(2H)-one (DHPZ), a new bisphenol-like monomer with twisted non-coplanar structure, with various molar proportions of 2,6-dichlorobenzonitrile (DCBN) to 4,4′-difluoro benzophenone (DFK) as coreactants in sulfolane at the present of anhydrous potassium carbonate. In order to obtain high-molecular weight polymers, DHPZ firstly polymerized with low-reactive DCBN for a given time at polymerization temperature after removal of water produced during the reaction, followed by addition of high-reactive DFK to continue the reaction until high-molecular weight polymers were obtained. These obtained copolymers had inherent viscosities between 0.45 and 0.80 dL/g in chloroform at a concentration of 0.5 g dL^?1 at 25 °C, and their number-average molecular weights were in the ranges from 2.2 × 10⁴ to 4.7 × 10⁴ with the polydispersity of 2.05–2.70. The structure of typical PPENK5050 was ambiguously confirmed by FT-IR and ¹H-NMR. All of the PPENKs were amorphous and soluble in dipolar aprotic solvents, involving N-methyl pyrrolidione, N,N-dimethylacetamide, and chloroform at room temperature. The resulting copolymers showed glass transition temperatures (T _gs) between 267 and 287 °C, and the T _g values of the copolymers were found to increase with increasing DCBN unit content in the polymer. Thermogravimetric studies showed that all of the polymers had 5 % weight loss temperatures ranging from 501 to 511 °C in nitrogen atmosphere. All of the PPENKs could be cast into transparent, strong, and flexible films. They displayed electrical surface resistivity of 10¹³ Ω, indicating their potential application in electronic field. Physical properties of PPENK5050, which exhibited the best mechanical properties, were measured according to ASTM plastic standards. The results indicated that PPENK5050 possessed excellent thermal properties with the heat deformation temperature of 270 °C, which was 100 °C higher than PEN? invented and commercialized by Idemitsu Kosan Company Limited. Its dielectric coefficient was 3.45 with the dielectric loss of 0.004 detected at 1 MHz. The other properties of PPENK5050 were equivalent to PEN?. They could be the promising materials as high-performance matrix in the application of polymer matrix composite, high-performance coating, adhesive, and membrane.     

Synthesis and photoluminescent properties of poly(aryl ether)s containing alternate emitting and electron‐transporting moieties

A new diphenylbutadiene‐containing bisphenol was successfully synthesized from benzylideneaniline and 4‐propenylanisole via an anil synthetic method. A series of copoly(arylene ether)s consisting of an alternate isolated blue chromophore (diphenylbutadiene) and an electron‐transporting moiety (1,3,4‐oxadiazole) was synthesized and characterized. High molecular weight copoly(arylene ether)s with an inherent viscosity of >0.5 dL/g were prepared by the nucleophilic displacement reaction of oxadiazole‐activated bis‐fluorocompounds with bisphenols. Introduction of ether linkages into the copolymers led to an enhanced solubility in organic solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidinone (NMP). The resulting copolymers can be cast into tough and transparent films. The copolymers were amorphous in structure with high glass transition temperatures ranging from 182.29 to 194.50°C. They also exhibited good thermal stability with the maximum decomposition temperatures higher than 500°C in nitrogen. The absorption peaks of these copolymers in thin films varied from 375 to 391 nm, while the photoluminescent peaks varied from 410 to 433 nm. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1645–1651, 2003     

Morphology,thermal and mechanical properties of glass fiber‐reinforced crosslinkable poly(arylene ether nitrile)

Crosslinkable poly(arylene ether nitrile)/glass fiber (PEN/GF) composites with high thermal stabilities and mechanical properties were prepared by a economically and environmentally viable method of melt extrusion and injection molding. The feasibility of using PEN/GF composites was investigated by evaluating its morphological, rheological, thermal, and mechanical properties. The morphology shows a good dispersion and strong interfacial interaction between PEN and GF. Thermal studies reveal that the thermal stabilities of PEN/GF are improved significantly with increase of GF content. Mechanical investigation manifested that GFs have strengthening effect (increase in flexural, tensile, and impact strength) on the mechanical performance of PEN composites. Most importantly, crosslinking reaction of PEN/GF composites can further improve their mechanical performances, because a couple of GFs are agglomerated by thermal motion and strong interfacial adhesion and the local agglomeration does not break the global uniform distribution. This work shows that both the enhancement of GF content and the crosslinking reaction of PEN/GF composites are two key factors influencing the thermal and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Enhanced dielectric permittivity and thermal conductivity of hexagonal boron nitride/poly(arylene ether nitrile) composites through magnetic alignment and mussel inspired co-modification

In this work, we present novel hexagonal boron nitride (h-BN)/poly(arylene ether nitrile) nanocomposites with high dielectric permittivity and thermal conductivity. For this purpose, the interfacial adhesion and orientation of nanofillers are the two key factors that need to be considered. Firstly, iron oxide was attached onto the surface of h-BN to obtain magnetically responsive property, which would realize the orientation of h-BN by applying an external magnetic field during the preparation process of PEN composites. Secondly, the magnetic h-BN was further modified by mussel-inspired method with dopamine and secondary functional monomer (KH550). It was found that the alignment of h-BN and improvement of interfacial adhesion resulted in the interesting properties of PEN composites. With addition of 30 wt% modified h-BN, the dielectric permittivity of PEN composites was increased from 3.2 of neat PEN to 16.4 (increased by 413%), and the low dielectric loss was remained. Meanwhile, the thermal conductivity was enhanced to 0.662 W/m K (increased by 140%) at the same loading content. In addition, the resulting h-BN/PEN nanocomposites maintained high mechanical strength and thermal stability even the nanofillers loading content reached 30 wt%. Therefore, the dielectric and thermally conductive h-BN/PEN composites with high mechanical strength and thermal stability have big advantages in the area of energy storage devices.     

Polyarylene ether nitrile/divinyl siloxane-bisbenzocyclobutene composite films: Curing reaction and thermal/mechanical/dielectric properties

Polymer dielectrics, are commonly used as insulating materials for electronic products. Light weight, good mechanical properties and high thermal conductivity are important properties. However, electrical and thermal parameters are interrelated, and it is challenging to have a dielectric polymer that is also resistant to high temperatures and high thermal conductivity. Hence, high-performance composite films were prepared by the method of post-solid phase chemical reaction using polyarylene ether nitrile (PEN) and divinyl siloxane-bisbenzocyclobutene (BCB) as raw materials. First, parameters of the curing reaction were determined by rheological and activation energy calculations. Then, through adjusting the content of BCB resin and treatment temperature, the performance of PEN/BCB composites could be tuned. Thermal properties have been studied by differential scanning calorimetry, dynamic mechanical analysis, thermal gravimetric analysis, and hot-disk method. Here, the PEN/BCB composite electric insulating materials with outstanding thermal performance (T_g: 208–400°C, T_5%: 469–544°C, thermal conductivity: 1.270–2.215 W/m K). Besides, its mechanical and dielectric properties were investigated in detail. It is noteworthy that the tensile strength of composite film can exceed a maximum of 130 MPa, which is 23.19% higher compared to the untreated one. Also, PEN/BCB composites own low dielectric constant (2.27–4.08 at 1 KHz), and the relationship between frequency or a wide temperature range and dielectric constant/loss is stable. Thus, it has a greater potential for applications in electronics in high-temperature environments.