Showing papers on "Phthalonitrile published in 2016"

Local-Excitation versus Charge-Transfer Characters in the Triplet State: Theoretical Insight into the Singlet–Triplet Energy Differences of Carbazolyl-Phthalonitrile-Based Thermally Activated Delayed Fluorescence Materials

Abstract: The singlet–triplet energy differences, ΔEST, of a series of carbazolyl-phthalonitrile (CzPN) derivatives were calculated at the levels of density functional theory (DFT) and time-dependent (TD) DFT using the gap-tuned, range-separated ωB97X functional. The studied CzPN derivatives include 4-(9H-carbazol-9-yl)phthalonitrile (CzPN), 4,5-di(9H-carbazol-9-yl)phthalonitrile (2CzPN), 3,4,5-tris(9H-carbazol-9-yl)phthalonitrile (3CzPN), and 3,4,5,6-tetra(9H-carbazol-9-yl)phthalonitrile (4CzPN). As additional Cz substituents are introduced, both the HOMO–LUMO energy gap, ΔEH–L, and ΔEST continuously decrease. Both natural transition orbital analysis and a quantitative assessment of the local-excitation (LE) and charge-transfer (CT) contributions to the excited states consistently demonstrate that the S1 states of all of the CzPN derivatives have a predominantly CT nature. In contrast, in the T1 state, the LE feature is dominant, but the CT character increases with the number of Cz groups. The decomposition of exc...

Crosslinked polyarylene ether nitrile film as flexible dielectric materials with ultrahigh thermal stability

Abstract: Dielectric film with ultrahigh thermal stability based on crosslinked polyarylene ether nitrile is prepared and characterized. The film is obtained by solution-casting of polyarylene ether nitrile terminated phthalonitrile (PEN-Ph) combined with post self-crosslinking at high temperature. The film shows a 5% decomposition temperature over 520 °C and a glass transition temperature (Tg) around 386 °C. Stable dielectric constant and low dielectric loss are observed for this film in the frequency range of 100–200 kHz and in the temperature range of 25–300 °C. The temperature coefficient of dielectric constant is less than 0.001 °C−1 even at 400 °C. By cycling heating and cooling up to ten times or heating at 300 °C for 12 h, the film shows good reversibility and robustness of the dielectric properties. This crosslinked PEN film will be a potential candidate as high performance film capacitor electronic devices materials used at high temperature.

Synthesis and properties of a novel high temperature pyridine‐containing phthalonitrile polymer

Abstract: A novel pyridine-containing aromatic phthalonitrile monomer, 2,6-bis[4-(3,4-dicyanophenoxy)benzoyl]pyridine (BCBP) was synthesized from the nitro displacement of 4-nitrophthalonitrile by the phenoxide of 2,6-bis (4-hydroxybenzoyl)pyridine (BHBP). 4-(Aminophenoxy) phthalonitrile (APPH) was selected to promote the curing reaction, and the curing behavior has been investigated by differential scanning calorimetric (DSC), suggesting a wide processing window about 64 °C. Different curing additive concentrations resulted in polymers with different crosslinking degrees and subsequently influenced the performance of resins. The resulting BCBP polymer exhibited high glass transition temperatures exceeding 400 °C, outstanding thermo-oxidative stability with weight retention of 95% at 530 °C, indicating a significant improvement in thermal properties endowed by pyridine units. Additionally, it also showed a lower overall water absorption after submersion in boiling water for 50 hours. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3819–3825

Oligomeric bisphenol A‐based PEEK‐like phthalonitrile‐cure and polymer properties

Abstract: The cure behavior and properties of oligomeric bisphenol A-based PEEK-like phthalonitrile (PN) are thoroughly examined in this article. The resin is easily processed from the melt at a relatively low temperature (150–200 °C) and the monomer cure occurs in a controlled manner as a function of the amine content and processing thermal conditions. Dynamic mechanical measurements and thermogravimetric analysis show that the polymer properties improve as the maximum PN postcure temperature is increased to 415 °C. The effects of the amine and polymer postcure conditions on the flexural and tensile properties of the PN polymer are investigated. The mechanical properties of the polymer are maximized after postcuring to moderate temperatures (330–350 °C). The polymer exhibits an average flexural strength and tensile strength at break of 117 and 71 MPa, respectively. After oxidative aging at 302 °C for 100 h, the polymer retains excellent mechanical properties. The average flexural and tensile strength retention of the polymers are 81 and 75%, respectively. Microscale calorimetric measurements reveal that the flammability parameters of the oligomeric PN are low compared to other thermosets. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3769–3777

Fluoro functional groups substituted cobalt(II), iron(II) phthalocyanines and their catalytic properties on benzyl alcohol oxidation

Abstract: In this study, phthalocyanine complexes (Co and Fe) bearing (2-{2-[3-(trifluoromethyl)phenoxy]ethoxy}ethoxy) groups at peripheral position were synthesized using the phthalonitrile derivative and characterized by IR, 1H-NMR, UV–Vis and mass spectrometry. Catalytic activity of Co(II) and Fe(II) phthalocyanines were investigated in the oxidation of benzyl alcohol with different oxygen sources. Determination of the optimal conditions for oxidation of benzyl alcohol, the catalytic reactions were carried out change the reaction temperature, oxidant/cat ratio, types of oxidants and subst./catalyst ratio.

Preparation and dielectric properties of copper phthalocyanine/graphene oxide nanohybrids via in situ polymerization

Abstract: A novel copper phthalocyanine-grafted graphene oxide (CuPc-g-GO) nanohybrid was prepared via in situ polymerization. Isophorone diisocyanate (IPDI) and 3-aminophenoxyphthalonitrile were employed to functionalize GO with phthalonitrile moieties (GO-IPDI-CN), which was subsequently polymerized with 1,3,5-tri-(3,4-dicyanophenoxy) benzene and CuCl, forming the copper phthalocyanine between the sheets of GO. The CuPc-g-GO and the intermediates were characterized by FTIR, TGA, DSC, XPS, SEM, UV–Vis, XRD, and AFM. The results suggested that CuPc was successfully grafted on the surface of GO, and the GO was completely exfoliated after the grafting of the CuPc. And the formation of the nanohybrids effectively enhanced the dielectric constant of CuPc, which was as high as 9.04 at 100 Hz, with an increment of 116 %, when the mass fraction of GO-IPDI-CN was 10 wt%.

Copolymerization of self-catalyzed phthalonitrile with bismaleimide toward high-temperature-resistant polymers with improved processability:

Abstract: Phthalonitrile and bismaleimide (BMI) have been considered as high-temperature-resistant materials in the fields of heterocyclic chemistry. In this work, a self-catalyzed phthalonitrile-containing ...

High photosensitized singlet oxygen generating zinc(II) and indium(III) acetate phthalocyanines containing 6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin groups

Abstract: The novel 6,8-di-tert-butyl-3-(p-hydroxyphenyl)coumarin (1) and its phthalonitrile derivatives named 4-[6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin]phthalonitrile (2), 3-[6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin]phthalonitrile (3), 4,5-bis[6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin]phthalonitrile (4) and 4-chloro-5-[6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin]phthalonitrile (5) were synthesized. These phthalonitrile derivatives were also converted to the corresponding zinc(II) (2a–5a) and indium(III)(OAc) (2b–5b) phthalocyanines bearing four or eight 6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin groups. All novel compounds synthesized in this study were fully characterized by elemental analysis and general spectroscopic techniques such as FT-IR, UV–vis, 1H NMR and mass. Additionally; spectral, photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of 6,8-di-tert-butyl-3-(p-oxyphenyl)coumarin substituted zinc(II) and indium(III)(OAc) phthalocyanines were investigated in N,N-dimethylformamide (DMF) solutions. The effects of number or position of the substituents and the type of central metal atoms on these properties were also determined. All studied phthalocyanines showed excellent solubility in general organic solvents. They also produced good singlet-oxygen and showed appropriate photodegradation by light irradiation.

Mechanical and physicochemical properties of matrices for fiber reinforced plastics based on low-melting phthalonitrile monomers

Abstract: The mechanical properties of cured phthalonitrile matrices for fiber reinforced plastics (FRP) based on low-melting phenylmethylsilanediyl-bis[oxymethylene(1,4-phenylene-4’-oxyphthalodinitrile)] (1) or its mixture with 1,3-phenylene-bis(oxy-4-phthalodinitrile) (2, comonomer) were studied. The flexural strength, Young’s modulus, fracture toughness, and some other characteristics of the cured resins based on monomer 1 (PN-1) and the mixture of monomers 1 and 2 (PN-1m) were determined. It is noted that the PN-1 resin can be processed by vacuum infusion and the PN-1m resin can be processed by compression injection molding. The developed resins are promising as materials for high-tech aerospace applications.

Thermally stable phthalonitrile matrixes containing siloxane fragments

Abstract: New low-melting phthalonitrile monomers suitable for the production of high-temperature matrixes for polymer composite materials are synthesized. After the introduction of siloxane bridges into a monomer, the glass-transition temperature decreases to–1–27°С, depending on the type of substituent at the silicon atom. These compounds are found to be sufficiently hydrolytically stable, despite the presence of sensitive siloxane bonds. The cured resin retain properties featured to the class of phthalonitriles, such as a high onset tеmperature of degradation (>530°С in argon), a high heat deflection temperature (>420°С), and char yield. The considered compounds make it possible to widen the temperature window for processing of phthalonitrile resins without any change in the properties of the final material.

New oligomeric containing aliphatic moiety phthalonitrile resins: their mechanical and thermal properties in presence of silane surface-modified zirconia nanoparticles

Abstract: This study deals with the influences of both the length of the aliphatic spacer within the phthalonitrile monomers backbones, and the amount of the silane surface modified zirconia nanoparticles on the mechanical and thermal properties of the so-called second generation phthalonitrile resins. Investigation on the curing behavior under differential scanning calorimeter outlined an important gain in the processability as the aliphatic spacer became longer. Results from the mechanical tests revealed that changing the length of the aliphatic spacer affects the mechanical properties in different ways. For instance, as the aliphatic spacer became longer, the toughness state was enhanced. At the same time, the tensile modulus and stress as well as the microhardness values were slightly reduced. It was also noticed that the introduction of the reinforcing phase caused an increase in all the tested mechanical properties. Furthermore, results from the thermogravimetric analysis and dynamic mechanical analysis revealed that reducing the length of the aliphatic spacer and adding nanofillers caused an increase in the thermal stability, storage modulus, and glass transition temperature. Moreover, a morphological study has been conducted under scanning electron microscope and transmission electron microscope to put in light the mechanisms of enhancements. Finally, this study demonstrated that the excellent properties of the phthalonitrile resins can be tailored by two ways either by monomers design or by inorganic nanoparticles reinforcement.