Understanding of the polymerization mechanism of the phthalonitrile-based resins containing benzoxazine and their thermal stability

Xu, Mingzhen; Ren, Dengxun; Chen, Lin; Li, Kui; Liu, Xiaobo

doi:10.1016/j.polymer.2018.04.004

Cited by 66 publications

(48 citation statements)

References 24 publications

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“…The curves generated from DSC of A-ph/CE prepolymers with various CE contents were plotted in Figure 3. As can be seen, A-ph/CE prepolymers exhibited double distinct exothermic peaks, which can be assigned to ring-opening polymerization of oxazine rings and ring-forming polymerization of nitrile groups, including phthalonitrile and isocyanate, respectively [27,28]. The initial cure temperatures of A-ph/CE prepolymers with 10, 20, 30, and 40 wt% CE appeared in the range at about 150-170°C.…”

Section: Results and Discussion 31 Curing Behaviors Of A-ph/cementioning

confidence: 92%

Copolymerization of phthalonitrile-based resin containing benzoxazine and cyanate ester: Curing behaviors, fiber-reinforced composite laminates and improved properties

Chen¹,

Ren²,

Chen³

et al. 2019

Express Polym. Lett.

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Curing behaviors and copolymerization mechanisms between phthalonitrile-based resin containing benzoxazine (A-ph) and cyanate ester (CE) were characterized and discussed. Results indicated that copolymerization between A-ph and CE were comprised of ring-opening polymerization of oxazine rings and ring-forming polymerization of cyanate and nitrile groups. From them, ring-opening of oxazine occurred preferentially, followed by ring-forming of cyanate and nitrile groups, which were promoted by active hydrogen and amine structures generated from ring-opening of oxazine. Moreover, with increasing the content of CE (≥40 wt%), self-polymerization of cyanate would dominate the components of the resulting composites and reduces the thermal stability of fiber-reinforced composite laminates. Additionally, mechanical properties of composite laminates were also affected by the content of CE. Composite laminates with 10 wt% CE showed the highest flexural strength (622 MPa). The improved mechanical properties were also verified with investigation of dynamic thermomechanical analysis and morphology of fracture surfaces. These findings are helpful to improve the thermosetting resins in terms of their chemical structure, material properties, and processability.

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Section: Results and Discussion 31 Curing Behaviors Of A-ph/cementioning

confidence: 92%

Copolymerization of phthalonitrile-based resin containing benzoxazine and cyanate ester: Curing behaviors, fiber-reinforced composite laminates and improved properties

Chen¹,

Ren²,

Chen³

et al. 2019

Express Polym. Lett.

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“…Although PBZs exhibit high glass temperature (Tg

170–340 °C), high char yield and better flammability resistance compared to conventional thermoset resins [ 1 ], the curing process takes place at relatively high temperatures (160–220 °C) restraining the usage of these polymers at industrial scale [ 8 ]. Thus, several strategies were developed in order to reduce the polymerization temperature by designing monomers with self-catalytic effect on the ROP as the –COOH and –OH groups showed effective contribution to accelerate the process [ 5 , 9 , 10 , 11 , 12 ]. However, the most significant results were obtained when extra-catalysts were employed such as cyanuric chloride [ 13 ], amines [ 14 ], sulfonates [ 15 ], lithium [ 16 ], and amine salts [ 17 , 18 ] that not only lower the ROP temperature but contribute to prolongation of the product life storage also.…”

Section: Introductionmentioning

confidence: 99%

Innovative Hyperbranched Polybenzoxazine-Based Graphene Oxide—Poly(amidoamines) Nanomaterials

2020

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The covalent functionalization of graphene oxide (GO) surface with hyperbranched benzoxazine (BZ) structures has been achieved using poly(amidoamine) dendrimers (PAMAM) of different generations. By increasing the PAMAM generation, multiple benzoxazine rings were synthesized decorating the GO layers. The polymerization process and the exfoliation behavior were investigated. The novel BZ-functionalized GO hybrid materials were characterized by a combination of techniques such as FT-IR, XPS, and 1H-NMR for the confirmation of benzoxazine formation onto the GO layer surfaces. Raman and XRD investigation showed that the GO stacking layers are highly disintegrated upon functionalization with hyperbranched benzoxazine monomers, the exfoliation being more probably to occur when lower PAMAM generation (G) is involved for the synthesis of hybrid GO-BZ nanocomposites. The polymerization of BZ rings may occur either between the BZ units from the same dendrimer molecule or between BZ units from different dendrimer molecules, thus influencing the intercalation/exfoliation of GO. DSC data showed that the polymerization temperature strongly depends on the PAMAM generation and a significant decrease of this value occurred for PAMAM of higher generation, the polymerization temperature being reduced with ~10 °C in case of GO-PAMAM(G2)-BZ. Moreover, the nanoindentation measurements showed significant mechanical properties improvement in case of GO-PAMAM(G2)-BZ comparing to GO-PAMAM(G0)-BZ in terms of Young modulus (from 0.536 GPa to 1.418 GPa) and stiffness (from 3617 N/m to 9621 N/m).

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“…However, the polymerization of pure PN monomers is difficult and time‐consuming even at high temperature. Various catalysts, such as organic compounds containing active hydrogen, benzoxazine, strong organic acid salts, amine salts, metals, and their salts, are usually employed to enhance the polymerization rate of the PN monomers. It is reported that PN resins might form triazine, isoindoline, and phthalocyanine structures through the collision between cyanos and catalysts with addition curing mechanism, and there are little or no volatile substances overflowed during the polymerization due to its unique curing mechanism …”

Section: Introductionmentioning

confidence: 99%

Introducing rigid pyrimidine ring to improve the mechanical properties and thermal‐oxidative stabilities of phthalonitrile resin

Yang

Chen

Zhang

et al. 2019

Polymers for Advanced Techs

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In this study, a novel phthalonitrile monomer containing pyrimidine ring, 4,6-bis[3-(3,4-dicya-nophenoxy)phenoxy]pyrimidine (BCPM), was successfully synthesized by nucleophilic substitution reaction with resorcinol, 4,6-dichloropyrimidine and 4nitrophthalonitrile. The BCPM monomer was cured by different temperature programs with 4-(aminophenoxy)phthalonitrile (APPH) as catalyst to give the polymers.The molecular structures of the BCPM monomer and the polymers were investigated by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Differential scanning calorimetric (DSC) analysis was performed to study the processability of the BCPM monomer, which showed a wide processing window of about 117°C. The mechanical properties and thermaloxidative stability of the polymer were characterized by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively, which indicated that the polymers exhibited excellent storage modulus, high glass transition temperature over 400°C, and outstanding thermal stability. The polymers also have low water absorption capacity and are suitable for humid environments.

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Understanding of the polymerization mechanism of the phthalonitrile-based resins containing benzoxazine and their thermal stability

Cited by 66 publications

References 24 publications

Copolymerization of phthalonitrile-based resin containing benzoxazine and cyanate ester: Curing behaviors, fiber-reinforced composite laminates and improved properties

Copolymerization of phthalonitrile-based resin containing benzoxazine and cyanate ester: Curing behaviors, fiber-reinforced composite laminates and improved properties

Innovative Hyperbranched Polybenzoxazine-Based Graphene Oxide—Poly(amidoamines) Nanomaterials

Introducing rigid pyrimidine ring to improve the mechanical properties and thermal‐oxidative stabilities of phthalonitrile resin

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