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     

Different filler effect of carbon nanotube and graphene nanoplatelet in the poly(arylene ether nitrile) matrix

The different filler effects of identical nitrile‐functionalized carbon nanotubes (CNTs) and graphene nanoplatelets (GNs) in a poly(arylene ether nitrile) (PEEN) matrix were investigated. PEEN/CNT and PEEN/GN composites were prepared by a facile solution‐casting method and systematically investigated for their differences in morphological, thermal and rheological properties. In the PEEN matrix GNs contact one another in a plane‐to‐plane manner, while CNTs are separated. Compared with PEEN/CNT composites, PEEN/GN composites below 2 wt% filler content exhibited higher thermal stability. Rheological properties of the resulting composites indicated that PEEN/GN composites were more sensitive to strain and exhibited higher η*, G′ and G″ than PEEN/CNT composites. The rheological percolation for CNTs is over 2 wt%, higher than that for GNs (around 1 wt%). All these differences originate from the different dimensions and structures of CNTs and GNs: GNs with a flake‐like structure and larger surface area can have stronger physical and interfacial interactions with the polymer matrix. This work gives a comparative view of the different filler effects that functionalized CNTs and GNs can have in the polymer host. With identical processing technology, GNs can show a stronger filler effect than CNTs. © 2012 Society of Chemical Industry     

Viscoelasticity and thermal stability of poly(arylene ether nitrile) nanocomposites with various functionalized carbon nanotubes

Poly(arylene ether nitrile) (PEN) nanocomposites containing various functionalized multi‐walled carbon nanotubes (MWCNTs) were prepared through a solution‐casting method. The as‐prepared PEN nanocomposites were investigated using parallel‐plate rheometry and thermogravimetric analysis, aimed at examining the effect of surface functionalization on the dispersion of MWCNTs from the viscoelastic and thermal properties. The linear viscoelasticy results indicated that 4‐aminophenoxyphthalonitrile‐grafted MWCNTs presented better dispersion in the PEN matrix than purified and carboxylic MWCNTs because the corresponding composite showed the lowest rheological percolation threshold, which was further confirmed from scanning electron microscopy, dissolution experiments and solution rheological experiments. The thermogravimetric analysis results revealed that the presence of 4‐aminophenoxyphthalonitrile‐grafted and carboxylic MWCNTs retarded the depolymerization compared with purified MWCNTs, showing a marked increase in the temperature corresponding to a loss of 5 wt% (increased by 14–22 °C) and maximum rate of decomposition (increased by 4–8 °C). Both the state of dispersion and the surface functionalization of MWCNTs are very important to the thermal stability of the PEN matrix. Copyright © 2011 Society of Chemical Industry     

Improving the thermal and mechanical properties of poly(arylene ether nitrile) films through blending high- and low-molecular-weight polymers

In present work, novel phthalonitrile end-capping poly(arylene ether nitrile)-phenyl (PEN-Ph) films with excellent mechanical properties as well as high glass transition temperature were prepared through blending high-molecular-weight PEN-Ph (HMW PEN-Ph) and low-molecular-weight PEN-Ph (LMW PEN-Ph). Then, the thermal and mechanical properties of the samples with different mass ratio of HMW PEN-Ph and LMW PEN-Ph were studied, and the effect of heat-treatment temperature on the performance of films was also investigated. The analysis results indicate that the crosslinking density as well as film formation can be controlled by adjusting the mass ratio of HMW PEN-Ph to LMW PEN-Ph. Besides, when the mass ratio of HMW PEN-Ph to LMW PEN-Ph is 5:2, the film treated at 340 °C possesses the best thermal and mechanical properties, with T_g of 218.9 °C and tensile strength of 104.8 MPa, increased by 10.9 °C and 16.6 MPa than pure HMW PEN-Ph film, respectively. Thus, the presence of LMW PEN-Ph makes the thermal and mechanical properties of the films improve dramatically, providing the possibility for the application in the electronics and high-temperature resistant fields. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48457.     

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     

Electrical properties of poly(arylene ether nitrile)/graphene nanocomposites prepared by in situ thermal reduction route

A series of functional metallo-supramolecular materials based on polyhedral oligomeric silsesquioxane (POSS) and phenanthroline ligand were prepared using a two-step approach. Firstly, using a phenanthroline ligand, an amino-functionalized transition metal complex was prepared by tin(II) chloride. In the second step, this metal complex was subsequently reacted with the octakis(3-chloropropyl)octasilsesquioxane, resulting for the metallosupramolecular polymers bearing POSS structure. All the synthesized compounds were fully characterized by spectroscopic analysis, thermal and electron microscopy techniques. Stimuli responsible properties of metallo-supramolecular materials were also investigated the reversibility upon external factors, such as electrochemical or the addition of competitive complexing ligands by electroanalytic techniques and UV–Vis spectroscopy. The electro- and chemo-responsive properties of the metallo-supramolecular materials were also improved. As a result, prepared phenanthroline-functionalized polyhedral silsesquioxane are good candidates for electronic, opto-electronic, and photovoltaic applications as a smart stimuli-responsive material.     

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     

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     

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.     

Effective thermal conductivity and thermal properties of phthalonitrile‐terminated poly(arylene ether nitriles) composites with hybrid functionalized alumina

A polymer‐based thermal conductive composite has been developed. It is based on a dispersion of micro‐ and nanosized alumina (Al₂O₃) in the phthalonitrile‐terminated poly (arylene ether nitriles) (PEN‐t‐ph) via solution casting method. The Al₂O₃ with different particle sizes were functionalized with phthalocyanine (Pc) which was used as coupling agent to improve the compatibility of Al₂O₃ and PEN‐t‐ph matrix. The content of microsized functionalized Al₂O₃ (m‐f‐Al₂O₃) maintained at 30 wt % to form the main thermally conductive path in the composites, and the nanosized functionalized Al₂O₃ (n‐f‐Al₂O₃) act as connection role to provide additional channels for the heat flow. The thermal conductivity of the f‐Al₂O₃/PEN‐t‐ph composites were investigated as a function of n‐f‐Al₂O₃ loading. Also, a remarkable improvement of the thermal conductivity from 0.206 to 0.467 W/mK was achieved at 30 wt % n‐f‐Al₂O₃ loading, which is nearly 2.7‐fold higher than that of pure PEN‐t‐ph polymer. Furthermore, the mechanical testing reveals that the tensile strength increased from 99 MPa for pure PEN‐t‐ph to 105 MPa for composites with 30 wt % m‐f‐Al₂O₃ filler loading. In addition, the PEN‐t‐ph composites possess excellent thermal properties with glass transition temperature (T_g) above 184°C, and initial degradation temperature (T_id) over 490°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41595.     

Effect of interfacial chemistry on the linear rheology and thermal stability of poly(arylene ether nitrile) nanocomposite films filled with various functionalized graphite nanoplates

Poly(arylene ether nitrile) (PEN) nanocomposites filled with functionalized graphite nanoplates (GNs) were prepared by a simple solution‐ casting method and then characterized by rheometer and thermogravimetric analysis (TGA). This study investigates how the surface treatment of GNs affects the GN dispersion state. The linear rheological test indicated that the 4‐aminophenoxyphthalonitrile‐grafted GN (GN‐CN) presented better dispersion in PEN matrix than purified GN because the corresponding composite showed the lower rheological percolation threshold, which was further confirmed by scanning electron microscopy and solution experiments. The TGA revealed that the presence of 4‐aminophenoxyphthalonitrile‐grafted GN retarded the depolymerization evidently compared with that of purified GN, showing remarkable increase in the temperatures corresponding to a weight loss of 5 wt % (increased by 21°C) and maximum rate of decomposition (increased by 9°C). Both the dispersion state and the surface functionalization of GN are very important to the thermal stability of PEN matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Multiblock poly(arylene ether nitrile) disulfonated poly(arylene ether sulfone) copolymers for proton exchange membranes: Part 1 synthesis and characterization

A series of multiblock copolymers based upon alternating segments of a hydrophilic disulfonated poly(arylene ether sulfone) and a hydrophobic fluorine-terminated poly(arylene ether benzonitrile) (6FPAEB) were synthesized and characterized for use as proton exchange membranes (PEM). The ion-exchange capacity of the block copolymers were varied by utilizing 4,4′-biphenol or hydroquinone in combination with 3,3′-disulfonated-4,4′-dichlorodiphenyl sulfone (SDCDPS) to form the hydrophilic segments. The alternating block copolymer morphology was achieved by using mild temperatures to link the oligomers together and minimize ether–ether interchange reactions. Both the 4,4′-biphenol and hydroquinone based membranes showed high proton conductivity with moderate water uptake and good mechanical properties. The block copolymers displayed nanophase separated morphologies, confirmed by transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS). The strong membrane performance was attributed to the multi-phase morphology.     

The properties (rheological,dielectric, and mechanical) and microtopography of spherical fullerene‐filled poly(arylene ether nitrile) nanocomposites

Poly (arylene ether nitrile)/fullerene (PEN/fullerene) nanocomposites were prepared by a facile solution‐cast method and the rheological, dielectric, mechanical, and morphological properties of the resulted nanocomposites were systematically studied and compared. Rheological studies showed PEN/fullerene nanocomposites percolation network formed at fullerene containing of 1.50 wt %, when the shear frequency was fixed at 0.1 Hz, the fitted rheological percolation threshold was about 1.55 wt %, very close to the experimental observations. The dielectric transaction occurs when the fullerene loading reached 1.50 wt %, that is very close to its rheological percolation threshold. At this point, PEN/fullerene nanocomposites also showed the optimal mechanical properties with a tensile strength of 93.6 MPa and modulus of 1951.5 MPa, which is increased by 27% and 15% compared with the pure PEN. SEM and TEM images have manifested the separate fullerene aggregated to fullerene bundles in PEN/fullerene nanocomposites, and the dispersion of fullerene bundles begin to go bad when the containing above 1.50 wt %. The PEN/fullerene nanocomposites can be widely used due to its excellent dielectric and mechanical performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40100.     

Iron phthalocyanine coatings on the surface of carbon fibers and their improved interfacial interactions with poly(arylene ether)nitrile

Riveted carbon fibers (CFs) were fabricated via in situ thermopolymerization. Iron phthalocyanine was like rivets distributed on the surface of the acidulated CFs. The rivets were characterized by scanning electron microscopy (SEM) and distributed uniformly on the surface of the CFs with a uniform microsphere size of 120 nm. Next, the pristine and riveted CFs were used to prepare fiber‐reinforced poly(arylene ether)nitrile (PEN)‐based composites with a hot‐press molding technique. The creep behaviors of PEN on the pristine and riveted CFs were investigated by dynamic rheological measurements. Among the samples, the viscosities changed with the frequency, and the stress relaxation and Cole–Cole plots are presented and discussed in detail. These results indicated better interlocking between the PEN chains and the rivets on the surface of the CFs. The dynamic mechanical properties of the composites were examined in three‐point bending mode with a dynamic mechanical analyzer. The results indicate that the reduction of the tan δ peak height may have been due to the improved interfacial adhesion between the CFs and PEN. Additionally, the interfacial morphologies of the CF‐reinforced PEN composites were monitored; this also confirmed the improved adhesion between the PEN chains and the riveted CFs in comparison with that of the pristine CFs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46466.     

The properties of some poly(arylene ether sulfones)

Some 2,4′-substituted poly(arylene ether sulfones) have been prepared and their properties compared with those of the conventional 4,4′ homopolymer. The introduction of the comonomer leads to a small increase in yield stress and to a greater tendency to brittle fracture, which can be demonstrated from fracture surface micrographs.     

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.     

Synergetic effects of graphene platelets and carbon nanotubes on the mechanical and thermal properties of epoxy composites

A remarkable synergetic effect between the multi-graphene platelets (MGPs) and multi-walled carbon nanotubes (MWCNTs) in improving the mechanical properties and thermal conductivity of epoxy composites is demonstrated. Stacking of individual two-dimensional MGPs is effectively inhibited by introducing one-dimensional MWCNTs. Long and tortuous MWCNTs can bridge adjacent MGPs and inhibit their aggregation, resulting in a high contact area between the MGP/MWCNT structures and the polymer matrix. Scanning electron microscope images of the fracture surfaces of the epoxy matrix showed that MWCNT/MGP hybrid nanofillers exhibited higher solubility and better compatibility than individual MWCNTs and MGPs did. The tensile strength of GD400-MWCNT/MGP/epoxy composites was 35.4% higher than that of the epoxy alone, compared to only a 0.9% increase in tensile strength for MGP/epoxy composites over the epoxy compound. Thermal conductivity increased by 146.9% using GD400-MWCNT/MGP hybrid fillers and 23.9% for MGP fillers, compared to non-derivatised epoxy.     

Synthesis of phenolphthalein/bisphenol A-based poly(arylene ether nitrile) copolymers: Preparation and properties of films

Poly(arylene ether nitrile) (PEN) is a class of high-performance engineering plastics of poly(arylene ether) with cyano groups as side groups, which can get improved thermal, mechanical, and electrical properties through simple molecular structure design. In this work, a series of PEN (BPA/PP based PEN) copolymers were synthesized with varying amounts of phenolphthalein and bisphenol A. The influence of the copolymer molecular structure variations on the thermal, mechanical, and dielectric properties of PEN copolymer films was investigated. The results demonstrated that the BPA/PP based PEN copolymer films have great mechanical properties and low dielectric constant, as well as enhanced thermal properties. The highest 5% weight loss temperature of 494.9°C was obtained by PEN-B7P3, while the highest glass transition temperature of 238.6°C was obtained by PEN-B3P7. Porous BPA/PP based PEN films prepared by non-solvent induced phase separation (NIPS) exhibited satisfactory mechanical properties and the highest tensile strength of 9.4 MPa was achieved. Moreover, the introduction of the phenolphthalein structure into the PEN molecular chain can improve the heat resistance of the PEN copolymers without deteriorating the dielectric properties, which gives the copolymers great potential as candidates for applications in flexible electronics and wireless communication.