End-functionalized thermoplastic-toughened phthalonitrile composites: influence on cure reaction and mechanical and thermal properties
TL;DR: In this paper, the feasibility of toughening novolac-phthalonitrile (NPN) resins using chemically modified poly(ether ether ketone) (PEEK).
Abstract: Phthalonitrile polymers are known for their high thermal stability and good mechanical properties. However, their brittle nature limits their application as structural composites in many critical areas. The present study investigates the feasibility of toughening novolac–phthalonitrile (NPN) resin using chemically modified poly(ether ether ketone) (PEEK). A telechelic PEEK bearing a phthalonitrile end group (PEEKPN) was synthesized via nucleophilic substitution of nitrophthalonitrile with the corresponding phenol–telechelic poly(ether ether ketone) (PEEKOH). Different compositions of NPN and PEEKOH–PEEKPN blends with curing agent, i.e. diaminodiphenylsulfone, were investigated for their cure behaviour and mechanical properties of their carbon fabric composites. In NPN–PEEKOH blends, crosslinking of the phthalonitrile groups was facilitated by phenol-mediated reactions resulting in the reduction of cure temperatures by around 130 °C with substantial improvement in thermal stability. Blending the resin with the thermoplastic enhanced the mechanical properties of the composites. The apparent flexural strength and impact strength of carbon fabric-reinforced composites were improved by more than 200 and 150%, respectively, on incorporation of 20 wt% PEEKOH in the NPN matrix. However, higher concentration of PEEKOH had a detrimental effect on the properties. Substitution of phenol end groups by phthalonitrile moieties led to integration of the PEEK moieties with the NPN matrix. However, it was not as conducive as PEEKOH for improving the matrix properties. The better performance of PEEKOH is attributed to the formation of polar heterocyclic groups like isoindoline by way of the phenol–nitrile reaction. © 2014 Society of Chemical Industry
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TL;DR: In this article, a tri-phthalonitrile phenyl polyhedral oligomeric silsesquioxane (TPnPh-POSS) was synthesized from trisilanol phenyl POSS and 4-nitrophthalonitriles.
Abstract: A novel tri-phthalonitrile phenyl polyhedral oligomeric silsesquioxane (TPnPh-POSS) was synthesized from trisilanol phenyl POSS and 4-nitrophthalonitrile. The structure of the TPnPh-POSS monomer was characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The phthalonitrile monomer was thermally polymerized with various concentrations (3, 4, and 5 wt%) of 4,4′-diaminodiphenyl sulfone (DDS) as the curing agent. The curing behavior of the monomer was investigated by differential scanning calorimetry. The influence of the content of the curing additive on the polymer properties was studied. Blends of TPnPh-POSS and diglycidyl ether of bisphenol A (epoxy resin) were successfully prepared. The thermal and mechanical properties of these blends with DDS as curing agent were evaluated and compared with the neat epoxy resin. The thermal stability of the cured polymers and epoxy/TPnPh-POSS blends was studied by thermogravimetric analysis. Dynamic mechanical analysis and ...
9 citations
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...The peaks observed at 1724 and 3443 cm 1 are indicative of the formation of polyisoindoline structures (Figure 3).(18,19) Figure 4 shows the (1)H NMR spectrum of TPnPhPOSS monomer....
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01 Jan 2018
TL;DR: The fiber-reinforced composites based on polymeric matrices have gained a lot of attention in the last few decades especially in aerospace and aircraft industries where high-performance (HP) lightweight structures are needed to replace some of the heavy metallic parts as discussed by the authors.
Abstract: Fiber-reinforced composites based on polymeric matrices have gained a lot of attention in the last few decades especially in aerospace and aircraft industries where high-performance (HP) lightweight structures are needed to replace some of the heavy metallic parts. Regardless of the fibers properties, only few polymeric matrices were able to meet the exigent and strict performances requirements of these applications. Nevertheless, the currently in-use polymers such as epoxies, polyimides, polybenzimidazoles, and cyanate ester resins can only afford compromises of these properties. Therefore, researchers have been targeting the replacement of these materials by other polymers with better properties. Phthalonitrile (PN) resins are advanced, polymeric materials exhibiting many interesting properties superior in many ways to the state-of-the art, HP polymers. Indeed, the last few decades showed a growing interest in the fiber-reinforced, PN composites and a consequent number of studies confirmed that the PN matrices can effectively replace the currently in-use polymers in many applications. Thus, this chapter reviews all the major works related to the subject, aiming to reveal the exceptional properties of the fiber-reinforced PN composites.
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TL;DR: In this paper, an easily processable phthalonitrile monomer (BBPN) with isobutyl segment was synthesized through nucleophilic substitution of 2,2-bis(4-hydroxyphenyl)butane (BPB) and 4-nitrophthalonitile, and its chemical structure was characterized with FTIR, 1H NMR and 13C NMR analyses.
Abstract: The present work reports on the synthesis of an easily processable phthalonitrile monomer (BBPN) with isobutyl segment. The effect of various curing agents on curing behaviors, thermal and adhesive properties of BBPN has been evaluated. The novel phthalonitrile monomer was synthesized through nucleophilic substitution of 2,2-bis(4-hydroxyphenyl)butane (BPB) and 4-nitrophthalonitrile, and its chemical structure was characterized with FTIR, 1H NMR and 13C NMR analyses. Four different aromatic diamines derived from different catalytic activities such as p-phenylenediamine (p-PD), m-tolidine (m-TB), o-tolidine (o-TB), and 2,2′-bis(trifluoromethyl)benzidine (TFMB) were used as curing agents. The curing kinetics of BBPN/aromatic diamine samples were investigated by non-isothermal differential scanning calorimetry (DSC) at different heating rates. The average activation energy was calculated based on Kissinger’s and Ozawa’s methods varied in the range of 66.61–79.00 kJ mol−1. The thermal properties of the obtained polymers were investigated by dynamic mechanical thermal analysis (DMA) and thermogravimetric analysis (TGA). Compared to other three systems, the cured BBPN/p-PD exhibited better thermal stability and higher glass-transition temperature (Tg), suggesting its higher degree of cross-linking. Moreover, the BBPN/diamine systems were used to bond aluminum sheet, and the average values of lap shear strengths were in the range of 13.8–19.6 MPa at room temperature and 9.2–11.5 MPa at 300 °C, respectively.
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TL;DR: In this paper, a new class of bisphthalonitrile functional bisimides used for polyimide precursors through 4,4′-bisphenol A dianhydride (BPADA) and various dicyanoaromatic monoamines, which were synthesized from aminophenols with 4-nitrophthalonitriles via a nucleophilic substitution reaction.
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TL;DR: In this paper, a kind of polyester-type phthalonitrile cyano resin (2,2-bis (((3-((4-(3,4-dicyanophenoxy) benzoyl)oxy)-2-(hydroxymethyl)-2-methylpropanoyl)-oxy)methyl) propane-1,3-diyl)bis(oxy)) b...
Abstract: In this article, a kind of polyester-type phthalonitrile cyano resin (2,2-bis (((3-((4-(3,4-dicyanophenoxy) benzoyl)oxy)-2-(hydroxymethyl)-2-methylpropanoyl)oxy)methyl) propane-1,3-diyl)bis(oxy)) b...
9 citations
References
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01 Jun 1977
TL;DR: Localized Chemical bonding Delocalized Chemical Bonding Bonding Weaker than Covalent Stereochemistry Carbocations, Carbanions, Free Radicals, Carbenes and Nitrenes Mechanisms and Methods of Determining them Photochemistry Acids and Bases Effects of Structure on Reactivity Aliphatic Nucleophilic Substitution Aromatic Electrophilic Substitutes Aliphatically Electrophilic Substitution Free-Radical Substitution Addition to Carbon-Carbon Multiple Bonds Adding to Carbon Hetero Multiple Bonds Eliminations Rearrangements Ox
Abstract: Localized Chemical bonding Delocalized Chemical Bonding Bonding Weaker than Covalent Stereochemistry Carbocations, Carbanions, Free Radicals, Carbenes and Nitrenes Mechanisms and Methods of Determining Them Photochemistry Acids and Bases Effects of Structure on Reactivity Aliphatic Nucleophilic Substitution Aromatic Electrophilic Substitution Aliphatic Electrophilic Substitution Free-Radical Substitution Addition to Carbon-Carbon Multiple Bonds Addition to Carbon- Hetero Multiple Bonds Eliminations Rearrangements Oxidations and Reductions The Literature of Organic Chemistry Classifications of Reactions by Type of Compound Synthesized.
4,885 citations
TL;DR: In this article, a series of sulfonated poly(ether ether ketone)s (SPEEKs) were prepared by sulfonation of commercial Victrex ® and Gatone ® PEEK for a comparative study of proton exchange membranes (PEM) intended for fuel cell applications.
880 citations
TL;DR: In this paper, le polymeres et composes modeles ont une resistivite electrique elevee and ne peuvent etre dopes par l'iode.
Abstract: Preparation a partir de bisphtalonitrile ponte avec de l'oxygene, du soufre ou du selenium. Insolubilite dans l'acide sulfurique indique une teneur elevee en phtalocyanine dans le polymere reticule ponte avec de l'oxygene. Les polymeres et composes modeles ont une resistivite electrique elevee et ne peuvent etre dopes par l'iode
255 citations
TL;DR: In this article, a multiple aromatic ether linked phthalonitrile was synthesized and characterized, which exhibited good structural integrity upon heating to elevated temperatures and exhibited excellent thermal properties along with long-term oxidative stability.
Abstract: A multiple aromatic ether linked phthalonitrile was synthesized and characterized. The oligomeric phthalonitrile monomer was prepared from the reaction of an excess amount of bisphenol A with 4,4'-difluorobenzophenone in the presence of K 2 CO 3 as the base in an N,N-dimethylformamide/toluene solvent mixture, followed by end capping with 4-nitrophthalonitrile in a two-step, one-pot reaction. The monomer properties were compared to those of the known resin 2,2-bis[4-(3,4-dicyanophenoxylphenyl]propane after being cured in the presence of bis[4-(4-aminophenoxy)-phenyllsulfone. Rheometric measurements and thermogravimetric analysis showed that the oligomeric phthalonitrile resin maintained good structural integrity upon heating to elevated temperatures and exhibited excellent thermal properties along with long-term oxidative stability. The ether-linked phthalonitrile resin absorbed less than 2.5% water by weight after exposure to an aqueous environment for extended periods.
209 citations
TL;DR: In this paper, a sulfone-containing diamine, bis[4-(4-aminophenoxy)phenyl] sulfone (p-BAPS), was used for phthalonitrile cure.
Abstract: Phthalonitrile monomers can be polymerized thermally in the presence of small amounts of curing agents into thermosetting polymers. The thermosets exhibit outstanding thermo-oxidative stability, display good mechanical properties, and offer promise as matrices for composite applications. The phthalonitrile cure reaction is typically accomplished with an aromatic diamine, 1,3-bis(3-aminophenoxy)benzene (m-APB), added in the range of 1.5–2% by weight of the monomer in the melt phase. This article addresses the cure reaction with a sulfone-containing diamine, bis[4-(4-aminophenoxy)phenyl] sulfone (p-BAPS), which shows lower volatility as determined from thermogravimetric studies (TGA) compared to m-APB at the processing temperatures typically employed for phthalonitrile cures. Rheometric studies conducted to monitor the viscosity increase during a cure reaction suggest that the cure reaction with m-APB is faster compared to the reaction with p-BAPS. Even though differences are seen in the initial cure rates, the final cured products are similar in terms of the glass transition temperatures and thermal and oxidative stabilities. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1885–1890, 1998
172 citations