Showing papers on "Phthalonitrile published in 2020"

A high-performance functional phthalonitrile resin with a low melting point and a low dielectric constant

Abstract: A monomer of fluorinated phthalonitrile, namely 4,4'-bis(p-perfluoro-phenol-(bis(p-phenol)propane-2,2-diyl)-p-oxy-diphthalonitrile) (PBDP), was synthesized by the nucleophilic substitution reaction of bisphenol A, decafluorobiphenyl and 4-nitrophthalonitrile. The structure of the monomer was characterized by nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The results indicated that the PBDP monomer was synthesized successfully. The monomer was cured in the presence of 4-(aminophenoxy)phthalonitrile (APPH) and the curing behaviour was investigated by differential scanning calorimetry (DSC), suggesting a low melting point of 96 °C and an excellent processing window (96-262 °C). Thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the fluorinated phthalonitrile resin possessed outstanding thermal and thermo-oxidative stabilities as well as good mechanical properties. The glass transition temperature was >400 °C and the 5% thermal degradation temperature was 501 °C. When the frequency was 50 MHz, the dielectric constant and dielectric loss of the polymer were 2.84 and 0.007, respectively. The PBDP resin has ultra-low water absorption of 0.77% and 1.4%, when exposed to an aqueous environment for 50 days at 24 °C and for 24 h at 100 °C, respectively. The prepared PBDP resin with outstanding thermal stability and low dielectric constant is an ideal candidate for aerospace industries, and microelectronic and other electronic packaging materials.

Phthalonitrile Resins Derived from Vanillin: Synthesis, Curing Behavior, and Thermal Properties

Abstract: Vanillin was used as sustainable source for phthalonitrile monomer synthesis, and allyl/propargyl ether moieties were introduced to improve the processability at the minimal cost of thermal properties. The synthesis route was optimized to minimize side-reactions and simplify post-processing, and the monomers were obtained in high purity and good yields. The curing behavior, mechanism, and processability of the monomers were studied, and the thermal properties of cured polymers were evaluated. Of the two monomers, the allyl ether-containing one exhibited a wide processing window of 185 °C, and was mainly cured into phthalocyanine and linear aliphatic structures through self-catalytic curing process. Also, the glass transition temperature was higher than 500 °C. In contrast, the propargyl ether-containing monomer could only be partially cured, and heat resistance was found to be compromised. Compared with traditional petroleum-based phthalonitrile resins, the bio-based monomers could be cured without the addition of catalysts, and improvement in processability was achieved at no cost of thermal performances.

Tri-functional phthalonitrile monomer as stiffness increasing additive for easy processable high performance resins

Abstract: A new tri-functional phthalonitrile monomer tris(3-(3,4-dicyanophenoxy)phenyl) phosphate (TPP) was first synthesized and characterized with the intent of increasing the cross-linking rate of phthalonitrile resins. By combining TTP and di-functional phthalonitrile with aromatic diamine easy-processable formulations (η 450 °C, T5% > 500 °C, TOS5% > 500 °C, Yc at 900 °C > 80%). TPP, the introduced monomer, can be used as a stiffness increasing additive with common di-functional phthalonitriles, and easy-processable formulations for cost-effective techniques of composites manufacturing.

Enhanced properties of phthalonitrile resins reinforced by novel phthalonitrile-terminated polyaryl ether nitrile containing fluorene group:

Abstract: Novel phthalonitrile resins (BPAPNs) were prepared by blending phthalonitrile-terminated oligomeric polyaryl ether nitrile, 4,4′-(1,3-phenylenebis(oxy))diphthalonitrile (PN), and 4-amino-4-(3,4-dic...

Optoelectronic parameters of peripherally tetra-substituted copper(II) phthalocyanines and fabrication of a photoconductive diode for various conditions

Abstract: In this study, the molecular structure of 4-(4-(trifluoromethoxy)phenoxy)phthalonitrile (1) has been elucidated and its supra-molecular dynamics have been revealed by the analysis of single crystal X-ray diffraction measurements. Compound (1) and its copper(II) phthalocyanine (2) were theoretically calculated with different basis sets. The Gibbs free energy values of copper(II) phthalocyanine (2) were investigated. The calculated values of IR, NMR and UV-vis spectra for compound (1) and its copper(II) phthalocyanine (2) were compared with the experimentally obtained values. The surface morphology properties of the compound (2) film for different magnifications were examined with its SEM images. We investigated the optical and optoelectronic parameters of compound (2) for different molarities. Also, we fabricated a diode based on compound (2) and examined its electronic characteristics under darkness, room light and 100 mW cm−2. Our diode exhibits a photoconductive property.

DFT analysis and electronic properties, and synthesis of tetra (9-phenyl-9H-xanthen-9-yl) oxy peripheral-substituted zinc phthalocyanine

Abstract: The 4-((9-phenyl-9H-xanthene-9-yl) oxy) phthalonitrile compound was synthesized and characterized as starting material. Zinc phthalocyanine was obtained by reaction of 4-((9-phenyl-9H-xanthen-9-yl) oxy) phthalonitrile with Zn(CH3COO)2. Novel compounds were characterized using mass spectra, UV–Vis spectroscopy, 1H-NMR, 13C NMR, and infrared spectroscopy. The fluorescence, emission, excitation, and absorption spectra of the zinc phthalocyanine compound were studied in tetrahydrofuran (THF). The determination of these properties is very useful for photodynamic therapy applications. Also, zinc phthalocyanine (Zn-Pc) was optimized with the basic set of 6-311G and LanL2DZ of the Density functional theory (DFT). The energy band-gap HOMO–LUMO of the molecule was determined. Chemical indices were calculated using HOMO–LUMO energies. The electrophilic region and the nucleophilic region were defined from the molecular electrostatic potential (MESP) maps. Dipole moment components have been calculated and can be considered as potential candidates for the design of non-linear optical materials.

Electrochemical and spectroelectrochemical characterizations of new tetra-substituted metallophthalocyanines bearing 4-(trifluoromethoxy)phenoxy groups on non-peripheral positions

Abstract: In this study, a series of non-peripherally tetra-substituted phthalocyanines [M = Zn(II), Co(II), and In(III)] was successfully prepared by cyclotetramerization of the phthalonitrile derivative bearing 4-(trifluoromethoxy)phenoxy group at 3-position. All newly synthesized compounds were characterized using spectroscopic methods, such as FT-IR, NMR, and UV–Vis spectroscopy. The effect of concentration on aggregation properties of the resulting phthalocyanines was investigated in different concentrations ranging from 4 × 10−6 to 14 × 10−6 M in THF. In addition, the spectral properties of the metallophthalocyanines were studied in various organic solvents. Besides, redox responses of metallophthalocyanines and their electro-optical responses were determined. Although {1(4),8(11),15(18),22(25)-tetrakis[4-(trifluoromethoxy)phenoxy]phthalocyaninato}cobalt(II) showed well-resolved reversible redox peaks depicting the anticipated electron transfer reactions, electrochemical investigation of its zinc(II) and indium(III) chloride analogs resulted in complex redox waves, and their chemical reversibility decreased with the aggregation of the complexes. The influence of the redox processes on the optical responses of metallophthalocyanines was studied with in situ spectroelectrochemistry measurements and the peak assignments and optical responses of the electrogenerated species were determined.

Investigation of the photoconductive properties of thiophene substituted metallo-phthalocyanines.

Abstract: The synthesis of 4-(thiophen-3-ylethynyl)phthalonitrile was achieved via the Sonogashira cross-coupling reaction. Herein, we report the synthesis of symmetrical metallo-phthalocyanines with cobalt, zinc, and manganese as the metal ions, and tetrakis(ethynylthiophene) groups substituted at the peripheral positions. The new compounds have been characterized by using mass, 1H NMR, 13C NMR, FT-IR and UV-vis spectroscopy. Dark and photoconductivity measurements were carried out on spin coated thiophene substituted metallo-phthalocyanines at various temperatures fixed between 300 and 440 K. Photocurrent generation and charge transport mechanisms are discussed as well. The evaluation of the photoconductive properties of these compounds indicated that the photocurrent generation efficiency and charge transport mechanism exhibited a strong temperature dependence. On the other hand, conductivity measurements revealed that the temperature dependence of the conductivity can be described by the Arrhenius type exponential equation under dark conditions. Furthermore, it was found that the photoconductive behavior of the film can be described successfully by the variable range hopping model for the whole investigated temperature range.