Abstract:A low melting point phthalonitrile monomer named 4,4'-((((((2cyano-1,3-phenylene)bis(oxy))bis(4,1-phenylene))bis(oxy))bis (4,1-phenylene))bis(oxy))diphthalonitrile (BOPN), was synthesized by nucleophilic substitution of 4,4'-oxydiphenol with 2,6dichlorobenzonitrile. The BOPN resin containing high-density aromatic ether bonds were prepared via bulk addition polymerization. Two kinds of polymers were prepared from BOPN monomer by using 4-(aminophenoxy)phthalonitrile (APPH) as the curing agent under different cur… Show more
“…Although the oligomers in this study showed the lowest densities of cyano groups, the cured resins with relatively high T g s could be obtained through the relatively moderate curing conditions, 10,24,40,66,67 which was probably due to the secondary crosslinking of the methylene group. 68 In the secondary crosslinking reaction, some sp 3 carbon atoms of specific structures participate in the formation of isoindoline or self-coupling, allowing to generate a dense network and increase T g of resin.…”
Section: Thermal Properties Of Post-curing Resinsmentioning
confidence: 60%
“…(PIPN-1-325 and PIPN-2-325 were prepared according to curing procedure a ; PIPN-1-350 and PIPN-2-350 were prepared according to curing procedure b ; PIPN-1-375 and PIPN-2-375 were prepared according to curing procedure c . ).Figure 8.A comparison of this work to other oligomeric PN resins 10, 24, 40, 66, 67 in terms of cyano groups density, post-curing temperature, curing duration, and T g .…”
Section: Resultsmentioning
confidence: 97%
“…Figure 8. A comparison of this work to other oligomeric PN resins10,24,40,66,67 in terms of cyano groups density, post-curing temperature, curing duration, and T g .…”
The meta- and para-catenated methylene-containing phthalonitrile oligomers were prepared from the reaction of an excess amount of 4,4′-(4,4′-isopropylidenediphenoxy) bis-(phthalic anhydride) (BPADA) with 4,4′-Methylenedianiline (MDA) in a N, N-dimethylformamide/ toluene solvent mixture, followed by end-capping agent with 4-nitrophthalonitrile or 4-phenoxyaniline in a two-step, one-pot reaction. Differential scanning calorimetry (DSC) showed that both PN oligomers exhibited low softening points. The self-catalyzed curing reactivity of the PN oligomers was confirmed by the isothermal rheological measurements. Fourier transform infrared spectroscopy (FTIR) and ultraviolet and visible spectrophotometry (UV–Vis) data of the pre-curing resins were employed to investigate the chemical structure of the pre-cured resins, suggesting that oligomers generated crosslinking sites, including triazine, isoindoline, and phthalocyanine. The results further confirmed the self-catalyzed curing reactivity of the oligomers. Thermal properties were investigated by dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA), demonstrating good thermal properties of the cured resins. The glass transition temperatures (Tgs) of PIPN-1-325, PIPN-1-350, PIPN-1-375 were in the range of 285–345°C, the 5% weight loss temperature (T5%) was observed at 482°C. The PIPN-2-325, PIPN-2-350, PIPN-2-375 showed Tgs ranging from 293 to 370°C, and T5% of the resins were in the range of 481–501°C. Then the isothermal rheological results of model compound and PN oligomers implied that the curing process of PN oligomers was closely related to the methylene-cyano radical thermal synergistic polymerization (TSP) effect proposed in our previous research, and then a revised curing mechanism (radical TSP mechanism) was proposed.
“…Although the oligomers in this study showed the lowest densities of cyano groups, the cured resins with relatively high T g s could be obtained through the relatively moderate curing conditions, 10,24,40,66,67 which was probably due to the secondary crosslinking of the methylene group. 68 In the secondary crosslinking reaction, some sp 3 carbon atoms of specific structures participate in the formation of isoindoline or self-coupling, allowing to generate a dense network and increase T g of resin.…”
Section: Thermal Properties Of Post-curing Resinsmentioning
confidence: 60%
“…(PIPN-1-325 and PIPN-2-325 were prepared according to curing procedure a ; PIPN-1-350 and PIPN-2-350 were prepared according to curing procedure b ; PIPN-1-375 and PIPN-2-375 were prepared according to curing procedure c . ).Figure 8.A comparison of this work to other oligomeric PN resins 10, 24, 40, 66, 67 in terms of cyano groups density, post-curing temperature, curing duration, and T g .…”
Section: Resultsmentioning
confidence: 97%
“…Figure 8. A comparison of this work to other oligomeric PN resins10,24,40,66,67 in terms of cyano groups density, post-curing temperature, curing duration, and T g .…”
The meta- and para-catenated methylene-containing phthalonitrile oligomers were prepared from the reaction of an excess amount of 4,4′-(4,4′-isopropylidenediphenoxy) bis-(phthalic anhydride) (BPADA) with 4,4′-Methylenedianiline (MDA) in a N, N-dimethylformamide/ toluene solvent mixture, followed by end-capping agent with 4-nitrophthalonitrile or 4-phenoxyaniline in a two-step, one-pot reaction. Differential scanning calorimetry (DSC) showed that both PN oligomers exhibited low softening points. The self-catalyzed curing reactivity of the PN oligomers was confirmed by the isothermal rheological measurements. Fourier transform infrared spectroscopy (FTIR) and ultraviolet and visible spectrophotometry (UV–Vis) data of the pre-curing resins were employed to investigate the chemical structure of the pre-cured resins, suggesting that oligomers generated crosslinking sites, including triazine, isoindoline, and phthalocyanine. The results further confirmed the self-catalyzed curing reactivity of the oligomers. Thermal properties were investigated by dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA), demonstrating good thermal properties of the cured resins. The glass transition temperatures (Tgs) of PIPN-1-325, PIPN-1-350, PIPN-1-375 were in the range of 285–345°C, the 5% weight loss temperature (T5%) was observed at 482°C. The PIPN-2-325, PIPN-2-350, PIPN-2-375 showed Tgs ranging from 293 to 370°C, and T5% of the resins were in the range of 481–501°C. Then the isothermal rheological results of model compound and PN oligomers implied that the curing process of PN oligomers was closely related to the methylene-cyano radical thermal synergistic polymerization (TSP) effect proposed in our previous research, and then a revised curing mechanism (radical TSP mechanism) was proposed.
A novel phthalazine‐based phthalonitrile resin was prepared by two different curing procedures. The phthalonitrile monomer, namely, 4,4′‐(((phthalazine‐1,4‐diylbis(oxy))bis(3,1‐phenylene))bis(oxy))diphthalonitrile (PDOP), was synthesized from the reaction of 1, 4‐dichloropthalazine, resorcinol, and 4‐nitrophthalonitrile. Its curing behavior and curing kinetics with 4‐(4‐aminophenoxy)phthalonitrile (APPH) were investigated by Differential Scanning Calorimetric (DSC). Isoconversional method based on Starink was applied to analyze the curing process of PDOP/APPH. The PDOP monomer exhibits a low melting point (89 °C) and a wide processing window (146 °C). The PDOP polymer mainly forms triazine, isoindoline, and phthalocyanine structure, as revealed by Fourier Transform Infrared (FTIR) spectroscopy, and its properties improved with the increase of post‐curing temperature and curing time. After post‐curing at 350 °C, the polymer has high storage modulus (3313 MPa), high glass‐transition temperature (380 °C), and outstanding thermal stability and thermal oxidation stability.
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